43 research outputs found
Alles verändert sich, damit es bleibt wie es ist!:erste Ergebnisse aus dem Forschungsprojekt "Geschlechterverhältnisse in autoritären und hybriden Regimen" am Fallbeispiel Nicaragua
Trotz weltweiter Demokratisierungsprozesse gehören autokratische und hybride Regierungssysteme nach wie vor zur politischen Realität. So werden aktuell ein Viertel aller Staaten und ein Drittel der Weltbevölkerung in Form von Monarchien, Präsidialautokratien, Familienautokratien, Militärjuntas sowie semi-demokratischen Systemen entweder autoritär oder begrenzt bzw. defizitär demokratisch regiert. Die Rolle von Geschlechterverhältnissen und die Bedeutung dieser Entwicklungen für die politische, soziale und ökonomische Stellung von Frauen, ist bisher von den Sozialwissenschaften nicht systematisch in den Blick genommen worden. Diesem Forschungsdesiderat widmet sich das Projekt „Geschlechterverhältnisse in autoritären und hybriden Regimen“ des Zentrums für Europäische Geschlechterstudien (ZEUGS) der Universität Münster. Der Journalartikel „Alles verändert sich, damit es bleibt, wie es ist“ fasst die ersten vielversprechenden Forschungsergebnisse sowohl theoretisch als auch praktisch am Beispiel der Zivilgesellschaft in Nicaragua zusammen
Large impact of the apoplast on somatic embryogenesis in Cyclamen persicum offers possibilities for improved developmental control in vitro
<p>Abstract</p> <p>Background</p> <p>Clonal propagation is highly desired especially for valuable horticultural crops. The method with the potentially highest multiplication rate is regeneration via somatic embryogenesis. However, this mode of propagation is often hampered by the occurrence of developmental aberrations and non-embryogenic callus. Therefore, the developmental process of somatic embryogenesis was analysed in the ornamental crop <it>Cyclamen persicum </it>by expression profiling, comparing different developmental stages of embryogenic cell cultures, zygotic vs. somatic embryos and embryogenic vs. non-embryogenic cell cultures.</p> <p>Results</p> <p>The analysis was based on a cDNA microarray representing 1,216 transcripts and was exemplarily validated by realtime PCR. For this purpose relative transcript abundances of homologues of a putative receptor kinase, two different glutathione S-transferases (GST), a xyloglucan endotransglycosylase (XET) and a peroxidase (POX) were quantitatively measured by realtime PCR for three different comparisons. In total, 417 genes were found to be differentially expressed. Gene Ontology annotation revealed that transcripts coding for enzymes that are active in the extracellular compartment (apoplast) were significantly overrepresented in several comparisons. The expression profiling results are underpinned by thorough histological analyses of somatic and zygotic embryos.</p> <p>Conclusions</p> <p>The putative underlying physiological processes are discussed and hypotheses on improvement of the protocol for <it>in vitro </it>somatic embryogenesis in <it>Cyclamen persicum </it>are deduced. A set of physiological markers is proposed for efficient molecular control of the process of somatic embryogenesis in <it>C. persicum</it>. The general suitability of expression profiling for the development and improvement of micropropagation methods is discussed.</p
A longer isoform of Stim1 is a negative SOCE regulator but increases cAMP-modulated NFAT signaling
Alternative splicing is a potent modifier of protein function. Stro mal interaction molecule 1 (Stim1) is the essential activator of
store-operated Ca2+ entry (SOCE) triggering activation of transcrip tion factors. Here, we characterize Stim1A, a splice variant with an
additional 31 amino acid domain inserted in frame within its
cytosolic domain. Prominent expression of exon A is found in astro cytes, heart, kidney, and testes. Full-length Stim1A functions as a
dominant-negative regulator of SOCE and ICRAC, facilitating
sequence-specific fast calcium-dependent inactivation and desta bilizing gating of Orai channels. Downregulation or absence of
native Stim1A results in increased SOCE. Despite reducing SOCE,
Stim1A leads to increased NFAT translocation. Differential proteo mics revealed an interference of Stim1A with the cAMP-SOCE
crosstalk by altered modulation of phosphodiesterase 8 (PDE8),
resulting in reduced cAMP degradation and increased PIP5K activ ity, facilitating NFAT activation. Our study uncovers a hitherto
unknown mechanism regulating NFAT activation and indicates
that cell-type-specific splicing of Stim1 is a potent means to regu late the NFAT signalosome and cAMP-SOCE crosstalk
Different localization of P2X4 and P2X7 receptors in native mouse lung - lack of evidence for a direct P2X4-P2X7 receptor interaction
IntroductionP2X receptors are a family of homo- and heterotrimeric cation channels gated by extracellular ATP. The P2X4 and P2X7 subunits show overlapping expression patterns and have been involved in similar physiological processes, such as pain and inflammation as well as various immune cell functions. While formation of P2X2/P2X3 heterotrimers produces a distinct pharmacological phenotype and has been well established, functional identification of a P2X4/P2X7 heteromer has been difficult and evidence for and against a physical association has been found. Most of this evidence stems, however, from in vitro model systems.MethodsHere, we used a P2X7-EGFP BAC transgenic mouse model as well as P2X4 and P2X7 knock-out mice to re-investigate a P2X4-P2X7 interaction in mouse lung by biochemical and immunohistochemical experiments as well as quantitative expression analysis.ResultsNo detectable amounts of P2X4 could be co-purified from mouse lung via P2X7-EGFP. In agreement with these findings, immuno-histochemical analysis using a P2X7-specific nanobody revealed only limited overlap in the cellular and subcellular localizations of P2X4 and P2X7 in both the native lung tissue and primary cells. Comparison of P2X4 and P2X7 transcript and protein levels in the respective gene-deficient and wild type mice showed no mutual interrelation between their expression levels in whole lungs. However, a significantly reduced P2rx7 expression was found in alveolar macrophages of P2rx4-/- mice.DiscussionIn summary, our detailed analysis of the cellular and subcellular P2X4 and P2X7 localization and expression does not support a physiologically relevant direct association of P2X4 and P2X7 subunits or receptors in vivo
Illuminating the life of GPCRs
The investigation of biological systems highly depends on the possibilities that allow scientists to visualize and quantify biomolecules and their related activities in real-time and non-invasively. G-protein coupled receptors represent a family of very dynamic and highly regulated transmembrane proteins that are involved in various important physiological processes. Since their localization is not confined to the cell surface they have been a very attractive "moving target" and the understanding of their intracellular pathways as well as the identified protein-protein-interactions has had implications for therapeutic interventions. Recent and ongoing advances in both the establishment of a variety of labeling methods and the improvement of measuring and analyzing instrumentation, have made fluorescence techniques to an indispensable tool for GPCR imaging. The illumination of their complex life cycle, which includes receptor biosynthesis, membrane targeting, ligand binding, signaling, internalization, recycling and degradation, will provide new insights into the relationship between spatial receptor distribution and function. This review covers the existing technologies to track GPCRs in living cells. Fluorescent ligands, antibodies, auto-fluorescent proteins as well as the evolving technologies for chemical labeling with peptide- and protein-tags are described and their major applications concerning the GPCR life cycle are presented
A consensus protocol for functional connectivity analysis in the rat brain
Task-free functional connectivity in animal models provides an experimental framework to examine connectivity phenomena under controlled conditions and allows for comparisons with data modalities collected under invasive or terminal procedures. Currently, animal acquisitions are performed with varying protocols and analyses that hamper result comparison and integration. Here we introduce StandardRat, a consensus rat functional magnetic resonance imaging acquisition protocol tested across 20 centers. To develop this protocol with optimized acquisition and processing parameters, we initially aggregated 65 functional imaging datasets acquired from rats across 46 centers. We developed a reproducible pipeline for analyzing rat data acquired with diverse protocols and determined experimental and processing parameters associated with the robust detection of functional connectivity across centers. We show that the standardized protocol enhances biologically plausible functional connectivity patterns relative to previous acquisitions. The protocol and processing pipeline described here is openly shared with the neuroimaging community to promote interoperability and cooperation toward tackling the most important challenges in neuroscience