Neues vom Antisemitismus: Zustände in Deutschland

Antisemitismus zählt zu den relativ unveränderten Einstellungen eines großen Teils der deutschen Bevölkerung. Ohne die Hartnäckigkeit vieler Akteure beim Kampf um die Zurückdrängung des Antisemitismus wäre die Lage in Deutschland noch viel dramtischer. In der Bekämpfung von Phobien verschiedenster Art – vom Rassismus bis zur Ausländerfeindlichkeit – nimmt der Kampf gegen Antisemitismus einen unverwechselbar eigenständigen Platz ein, der nicht relativiert werden darf. In diesem Band werden die lange Entstehungs- und Entwicklungsgeschichte von Antisemitismus in Deutschland, aber auch aktuelle Aspekte dieses Phänomens beleuchtet. In einem zweiten Teil stehen die Referate und ausgewählte Diskussionsbeiträge der Antisemitismus-Konferenz der Rosa-Luxemburg-Stiftung vom 11. Januar 2007 im Zentrum. Im Dokumententeil wird die »Working Definition of Antisemitism« veröffentlicht, die allen in der Auseinandersetzung mit dem Antisemitismus Engagierten eine Orientierung bietet

The role of bounded rationality and imperfect information in subgame perfect implementation - an empirical investigation

In this paper we conduct a laboratory experiment to test the extent to which Moore and Repullo’s subgame perfect implementation mechanism induces truth-telling, both in a setting with perfect information and in a setting where buyers and sellers face a small amount of uncertainty regarding the good’s value. We find that Moore–Repullo mechanisms fail to implement truth-telling in a substantial number of cases even under perfect information about the valuation of the good. Our data further suggests that a substantial proportion of these lies are made by subjects who hold pessimistic beliefs about the rationality of their trading partners. Although the mechanism should—in theory—provide incentives for truth-telling, many buyers in fact believe that they can increase their expected monetary payoff by lying. The deviations from truth-telling become significantly more frequent and more persistent when agents face small amounts of uncertainty regarding the good’s value. Our results thus suggest that both beliefs about irrational play and small amounts of uncertainty about valuations may constitute important reasons for the absence of Moore–Repullo mechanisms in practice

Elucidating the architecture of the type III secretion system export apparatus

Type III secretion systems (T3SS) are a widespread virulence factor in Gram negative bacteria. They contain an inner membrane spanning sub-complex termed the export apparatus, made up of five proteins. The export apparatus translocates effector proteins designated for the host cytoplasm across the inner membrane, is involved in substrate recognition and in substrate specificity switching. Knowing the structure of their components is critical for investigating makeup, assembly, and function of macromolecular machines. This has remained a technical challenge in particular for large, hydrophobic membrane-spanning protein complexes like the T3SS. I determined the stoichiometry of the complete SPI-1 T3SS of Salmonella enterica serovar Typhimurium and the topology of the export apparatus proteins. For the stoichiometric analysis, I used a mass spectrometry approach based on two complementary protocols for gentle complex purification combined with stable isotope-labelled standards. Previous structural analyses have revealed the stoichiometry of base components, but the stoichiometry of the essential hydrophobic export apparatus components and of the ’inner rod’ protein PrgJ remained unknown. Here, I provide evidence that the export apparatus of T3SS contains five SpaP, one SpaQ, one SpaR, and one SpaS. Additionally I can confirm the suggested stoichiometries of InvA and the base components in situ. Furthermore, I present evidence that no more than six PrgJ are involved in the formation of the ’inner rod’. I assessed the topology of the five export apparatus transmembrane proteins using computer predictions and a substituted cysteine accessibility method. The position of the trans- membrane helices and orientation of the loops of InvA, SpaS and one of the minor export apparatus proteins, SpaP, were mapped experimentally. The prediction could be largely confirmed for SpaS and partly for InvA, while one large periplasmic loop could be confirmed for SpaP. Providing this structural information will facilitate efforts to obtain an atomic view of T3SS. The topology and stoichiometry identification of these proteins alongside with recent interaction studies are important steps in determining the exact placement of the export apparatus in T3SS and ultimately facilitates elucidation of the function of each component

Pre- and Post-Processing Workflow for Affinity Purification Mass Spectrometry Data

The reliable detection of protein–protein interactions by affinity purification mass spectrometry (AP-MS) is crucial for the understanding of biological processes. Quantitative information can be used to separate truly interacting proteins from false-positives by contrasting counts of proteins binding to specific baits with counts of negative controls. Several approaches have been proposed for computing scores for potential interaction proteins, for example, the commonly used SAINT software. However, it remains a subjective decision where to set the cutoff score for candidate selection; furthermore, no precise control for the expected number of false-positives is provided. In related fields, successful data analysis strongly relies on statistical pre- and post-processing steps, which, so far, have played only a minor role in AP-MS data analysis. We introduce a complete workflow, embedding either the scoring method SAINT or alternatively a two-stage Poisson model into a pre- and post-processing framework. To this end, we investigate different normalization methods and apply a statistical filter adjusted to AP-MS data. Furthermore, we propose permutation and adjustment procedures, which allow the replacement of scores by statistical p values. The performance of the workflow is assessed on simulations as well as on a study focusing on interactions with the T3SS in Salmonella Typhimurium. Preprocessing methods significantly increase the number of detected truly interacting proteins, while a constant false-discovery rate is maintained. The software solution is freely available

Determination of the Stoichiometry of the Complete Bacterial Type III Secretion Needle Complex Using a Combined Quantitative Proteomic Approach

Precisely knowing the stoichiometry of their components is critical for investigating structure, assembly, and function of macromolecular machines. This has remained a technical challenge in particular for large, hydrophobic membrane-spanning protein complexes. Here, we determined the stoichiometry of a type III secretion system of Salmonella enterica serovar Typhimurium using two complementary protocols of gentle complex purification combined with peptide concatenated standard and synthetic stable isotope-labeled peptide-based mass spectrometry. Bacterial type III secretion systems are cell envelope-spanning effector protein-delivery machines essential for colonization and survival of many Gram-negative pathogens and symbionts. The membrane-embedded core unit of these secretion systems, termed the needle complex, is composed of a base that anchors the machinery to the inner and outer membranes, a hollow filament formed by inner rod and needle subunits that serves as conduit for substrate proteins, and a membrane-embedded export apparatus facilitating substrate translocation. Structural analyses have revealed the stoichiometry of the components of the base, but the stoichiometry of the essential hydrophobic export apparatus components and of the inner rod protein remain unknown. Here, we provide evidence that the export apparatus of type III secretion systems contains five SpaP, one SpaQ, one SpaR, and one SpaS. We confirmed that the previously suggested stoichiometry of nine InvA is valid for assembled needle complexes and describe a loose association of InvA with other needle complex components that may reflect its function. Furthermore, we present evidence that not more than six PrgJ form the inner rod of the needle complex. Providing this structural information will facilitate efforts to obtain an atomic view of type III secretion systems and foster our understanding of the function of these and related flagellar machines. Given that other virulence-associated bacterial secretion systems are similar in their overall buildup and complexity, the presented approach may also enable their stoichiometry elucidation

Pre- and Post-Processing Workflow for Affinity Purification Mass Spectrometry Data

The reliable detection of protein–protein interactions by affinity purification mass spectrometry (AP-MS) is crucial for the understanding of biological processes. Quantitative information can be used to separate truly interacting proteins from false-positives by contrasting counts of proteins binding to specific baits with counts of negative controls. Several approaches have been proposed for computing scores for potential interaction proteins, for example, the commonly used SAINT software. However, it remains a subjective decision where to set the cutoff score for candidate selection; furthermore, no precise control for the expected number of false-positives is provided. In related fields, successful data analysis strongly relies on statistical pre- and post-processing steps, which, so far, have played only a minor role in AP-MS data analysis. We introduce a complete workflow, embedding either the scoring method SAINT or alternatively a two-stage Poisson model into a pre- and post-processing framework. To this end, we investigate different normalization methods and apply a statistical filter adjusted to AP-MS data. Furthermore, we propose permutation and adjustment procedures, which allow the replacement of scores by statistical <i>p</i> values. The performance of the workflow is assessed on simulations as well as on a study focusing on interactions with the T3SS in <i>Salmonella Typhimurium</i>. Preprocessing methods significantly increase the number of detected truly interacting proteins, while a constant false-discovery rate is maintained. The software solution is freely available

Pre- and Post-Processing Workflow for Affinity Purification Mass Spectrometry Data

The reliable detection of protein–protein interactions by affinity purification mass spectrometry (AP-MS) is crucial for the understanding of biological processes. Quantitative information can be used to separate truly interacting proteins from false-positives by contrasting counts of proteins binding to specific baits with counts of negative controls. Several approaches have been proposed for computing scores for potential interaction proteins, for example, the commonly used SAINT software. However, it remains a subjective decision where to set the cutoff score for candidate selection; furthermore, no precise control for the expected number of false-positives is provided. In related fields, successful data analysis strongly relies on statistical pre- and post-processing steps, which, so far, have played only a minor role in AP-MS data analysis. We introduce a complete workflow, embedding either the scoring method SAINT or alternatively a two-stage Poisson model into a pre- and post-processing framework. To this end, we investigate different normalization methods and apply a statistical filter adjusted to AP-MS data. Furthermore, we propose permutation and adjustment procedures, which allow the replacement of scores by statistical <i>p</i> values. The performance of the workflow is assessed on simulations as well as on a study focusing on interactions with the T3SS in <i>Salmonella Typhimurium</i>. Preprocessing methods significantly increase the number of detected truly interacting proteins, while a constant false-discovery rate is maintained. The software solution is freely available