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A recent randomized study of whipworm Trichuris suis ova (TSO) in ileal Crohn’s disease failed to demonstrate a clinical benefit compared to placebo after 12 weeks. Nonetheless, it has recently been shown that the spontaneous small intestinal inflammatory changes in Nod2-/- (Nucleotide-binding oligomerization domain 2) mice could be substantially ameliorated when these mice were colonized by Trichuris muris. Those and complementary epidemiologic findings in humans lead to the hypothesis that helminths may be advantageous only in patients carrying defective NOD2 variants. Thus, 207 participants of the TSO trial were retrospectively genotyped for six functional NOD2 genetic variants to evaluate whether the treatment outcome differed in patients carrying NOD2 variants. We observed no significant association of the NOD2 variants or their haplotypes with clinical outcome after TSO treatment.
Development of T cells in the thymus is tightly controlled to continually produce functional, but not autoreactive, T cells. miRNAs provide a layer of post-transcriptional gene regulation to this process, but the role of many individual miRNAs in T-cell development remains unclear. miR-21 is prominently expressed in immature thymocytes followed by a steep decline in more mature cells. We hypothesized that such a dynamic expression was indicative of a regulatory function in intrathymic T-cell development. To test this hypothesis, we analyzed T-cell development in miR-21-deficient mice at steady state and under competitive conditions in mixed bone-marrow chimeras. We complemented analysis of knock-out animals by employing over-expression in vivo. Finally, we assessed miR-21 function in negative selection in vivo as well as differentiation in co-cultures. Together, these experiments revealed that miR-21 is largely dispensable for physiologic T-cell development. Given that miR-21 has been implicated in regulation of cellular stress responses, we assessed a potential role of miR-21 in endogenous regeneration of the thymus after sublethal irradiation. Again, miR-21 was completely dispensable in this process. We concluded that, despite prominent and highly dynamic expression in thymocytes, miR-21 expression was not required for physiologic T-cell development or endogenous regeneration.
On July 10, 1798, the German ensemble at the Vienna court theater presented the premiere performance of 'Die Hochzeit des Figaro', the first production of Mozart and Da Ponte's 'Le nozze di Figaro' – and indeed of any Mozart-Da Ponte work – at the court theater since Mozart's death and Da Ponte's departure from the imperial capital. A few months later, on December 11, 1798, a new production of Don Giovanni, titled Don Juan, arrived at the court theater stage. On September 19, 1804, a production of Così fan tutte followed, under the title 'Mädchentreue'. Although the productions were not extraordinarily successful in terms of performance numbers, they represented important trends in the Viennese reception of Mozart's operas that were to continue throughout the early nineteenth century. In particular, these productions left behind numerous records about the convoluted processes through which theatrical works were approved, re-approved, and revised before reaching the stage in Vienna around 1800. Particularly prominent among these processes was censorship. Yet, as this article shows, Viennese censors worked in tandem with numerous private and public agents who likewise contributed to the final shape of pre-existing works' adaptations. An examination of the censorial approaches to Mozart's Don Giovanni and Così fan tutte in Vienna around 1800 shows that late Enlightenment censorship was contradictory and multidirectional and should be considered not as a force of restriction but as an element that affected artworks in ways similar to other social, political, and cultural factors, such as patronage, audience structure, and various social and political ideologies.
To date, chemicals are used ubiquitous in everyday life and an increasing consumption of pharmaceuticals and personal care products and industrial chemicals results in an increased water pollution. Conventional wastewater treatment plants are not able to completely remove the variety of (polar) organic compounds from today’s wastewater and thus serve as constant key point sources for the unintentional release of (micro-)pollutants into the aquatic environment. Anthropogenic micropollutants are detectable in very low concentrations in almost every aquatic compartment and may cause adverse effects on aquatic organisms. Considering the current situation of water pollution and to enhance water quality with regard to environmental and human health, the implementation of advanced wastewater treatment technologies, such as ozonation and activated carbon filtration was extensively discussed and investigated in recent years. Yet, besides their advantages regarding the efficient removal of a variety of recalcitrant, organic compounds as well as pathogens from the wastewater, it is known that especially the treatment with ozone may lead to the formation of largely unknown ozonation by-products with often unknown toxicity and unknown threats to human and the environment. To address these topics the joint research project TransRisk aimed at the “characterization, communication and minimization of risks originating from emerging contaminants and pathogens in the water cycle”. Within this research project the present thesis focuses on the ecotoxicological investigation of emerging waterborne contaminants, including their potential transformation products (TPs). Additionally, focus was laid on the investigation of combined effects of anthropogenic contaminants and pathogens with effects especially on aquatic invertebrate organisms.
The potential ecotoxicological effects of the antiviral drug acyclovir and two of its structurally identified TPs, were investigated on three aquatic organisms (Raphidocelis subcapitata, Daphnia magna and embryos of Danio rerio). While the parent compound acyclovir caused no acute toxicity up to a tested concentration of 100 mg/l on any of the investigated organisms, both TPs were shown to exhibit an increased aquatic toxicity. Carboxy-acyclovir, the biodegradation product of acyclovir, significantly reduced reproduction of D. magna by 40% at 102 mg/l, and the ozonation product COFA significantly inhibited growth of green algae R. subcapitata (EC10 = 14.1 mg/l). In the present case, advanced wastewater treatment was shown to lead to the formation of TPs, that reveal a higher toxicity towards investigated organisms, than the parent compound. Results highlight the necessity of further research related to the topic of identification and characterization of TPs, formed during advanced wastewater treatment processes.
To investigate the potential reduction or enhancement of toxic effects of nine differently treated wastewater effluents, selected bioassays with Daphnia magna, Lumbriculus variegatus and Lemna minor were conducted in flow-through test systems on a pilot treatment plant. The different treatment processes included ozonation of conventional biological treatment, with subsequent filtration processes as well as membrane bioreactor treatment in combination with ozonation. While exposure to the conventionally treated wastewater did not result in significant impairing effects on D. magna and L. minor, a reduced abundance of L. variegatus (by up to 46%) was observed compared to the medium control. Subsequent ozonation and additional filtration of the wastewater enhanced water quality, visible in an improved performance of L. variegatus. In general, direct evidence for the formation of toxic TPs due to the advanced wastewater treatments was not found, at least not in concentrations high enough to cause measurable effects in the investigated test systems. Additionally, no evidence for immunotoxic effects of the investigated wastewater effluents were observed. Yet, study-site- and species-specific effects hindered the definite interpretation of results. That underline the importance of a suitable test battery consisting of representatives of different taxonomic groups and trophic levels, to ensure a comprehensive evaluation of the complex matrix of wastewater and to avoid false-negative or false-positive results.
With aim to improve knowledge regarding immunotoxicity in invertebrates, the potential immunotoxic effects of the immunosuppressive pharmaceutical cyclosporine A (CsA) were investigated by applying the host-parasite model system Daphnia magna – Pasteuria ramosa in an adapted host resistance assay. Co-exposure to CsA and Pasteuria synergistically affected long-term survival of D. magna. Additionally, the enhanced virulence of the pathogen upon chemical co-exposure was expressed in synergistically increased infection rates and an increased speed of Pasteuria-induced host sterilization. In conclusion, results provide evidence for a suppressed disease resistance in a chemically stressed invertebrate host, highlighting the importance of investigating the conjunction of environmental pollutants and pathogens in the environmental risk assessment of anthropogenic pollutants.
In homeostatic scaling at central synapses, the depth and breadth of cellular mechanisms that detect the offset from the set-point, detect the duration of the offset and implement a cellular response are not well understood. To understand the time-dependent scaling dynamics we treated cultured rat hippocampal cells with either TTX or bicucculline for 2 hr to induce the process of up- or down-scaling, respectively. During the activity manipulation we metabolically labeled newly synthesized proteins using BONCAT. We identified 168 newly synthesized proteins that exhibited significant changes in expression. To obtain a temporal trajectory of the response, we compared the proteins synthesized within 2 hr or 24 hr of the activity manipulation. Surprisingly, there was little overlap in the significantly regulated newly synthesized proteins identified in the early- and integrated late response datasets. There was, however, overlap in the functional categories that are modulated early and late. These data indicate that within protein function groups, different proteomic choices can be made to effect early and late homeostatic responses that detect the duration and polarity of the activity manipulation.
In the latest contribution to the Democracy Papers, Thomas Zittel explores when and how polarization becomes a cause for democratic anxiety. He argues that polarization over traditional policy issues is not in itself harmful, and can even be beneficial for democracies. However, he warns that polarization in which parties become divided over the acceptable rules of the game is a problem for democracies. Unfortunately, this latter type of division is increasingly common on both sides of the Atlantic today.
The individual parameter
(2018)
The present thesis tackles the unification of two-dimensional semantic systems, which are designed to deal with context-dependency of a certain kind i.e. indexicality, with dynamic theories of meaning, designed to capture facts about anaphoricity and the distribution of definite and indefinite articles. The need for a more principled look at this unification is twofold. Firstly, there is an overlap of these two families of theories in terms of empirical data, namely third person personal pronouns, as well as definite descriptions. Both kinds of expressions have anaphoric as well as non-anaphoric usages, whereas some of the latter ones can be captured in terms of indexicality. But, on the other hand, no language, especially not German and English, the main sources of data in this thesis, seems to distinguish these two usages formally, i.e. by employing different expressions. Hence the need for a unified framework in which this sort of ambiguity can be treated. Secondly, the theoretical state is dissatisfactory in the sense that the families of theories take very disparate forms that are not easy to relate conceptually.
The overlap in empirical area of application strongly suggests that this dichotomy is an artifact of the way these theories traditionally are developed and justified. This thesis seeks to overcome this state of the field. It proceeds as follows.
The first chapter discusses the way in which theories indexicality are designed. After taking a closer look some hallmarks of these theories such as the notions of index- and context-dependency themselves, double indexing, etc., it develops a notion of index dependency that makes use of a more complex individual parameter than the one that is usually assumed in the literature. Apart from agents and addressees, the two standard components of indices that represent contexts, additional objects are assumed. This leads to a variant of the semantics of deictically used third person expression that is called ‘indexical theory of demonstratives’, which is then investigated further.
The second chapter discusses the classics of dynamic semantics: DRT, DPL, and FCS. It arrives at the common core of all of these theories that consists in the assumption of a novel sort of variable namely active variables as opposed to free and bound ones that are intended to model the behavior of (in)definite descriptions and pronouns. The projection behavior of these variables or discourse referents is described either in (discourse-)syntactic or semantic terms. The chapter also arrives at a new formulation of the uniqueness condition that is thought to be part of the semantics of definite descriptions and sketches an account of transparent negation.
The third chapter then combines the insights of the previous ones by developing the notion of representation that connects the entities of evaluation of the first chapter i.e. indices with those of the second namely sets of assignments, a.k.a. files. The formal language that emerged in the second chapter is endowed with two kinds of variables for situations to allow for double indexing within a dynamic setting. A novel interpretation mechanism for the so designed language is proposed, which is shown to capture not only those aspects that are known to exist in two-dimensional frameworks, but also certain other index-index interactions that are described in yet another body of literature.
The final chapter discusses potential flaws of the theory and sketches an account of allegedly bound indexicals that is compatible with Kaplan’s infamous ban on monsters.
Application of a developed tool to visualize newly synthesized AMPA receptor components in situ
(2018)
The information flow between neurons happens at contact points, the synapses. One underlying mechanism of learning and memory is the change in the strength of information flow in selected synapses. In order to match the huge demand in membranes and proteins to build and maintain the neurites' complex architecture, neurons use decentralized protein synthesis. Many candidate proteins for local synthesis are known, and the need of de novo synthesis for memory formation is well established. The underlying mechanisms of how somatic versus dendritic synthesis is regulated are yet to be elucidated. Which proteins are newly synthesized in order to allow learning?
In this thesis protein synthesis is studied in hippocampal neurons. The fractional distribution of somatic and dendritic synthesis for candidate proteins and their subsequent transport to their destination are investigated using a newly developed technique. In the first part of this study we describe the development of this technique and use it in the second part to answer biological questions.
We focus here on AMPA receptor subunits, the key players in fast excitatory transmission. AMPA receptors contain multiple subunits with diverse functions. It remains to be understood, when and where in a neuron these subunits come together to form a protein complex and how the choice of subunits is regulated.
The investigation of the subunits' site of synthesis and redistribution kinetics in this study will help us to understand how neurons are able to change their synaptic strength in an input specific manner which eventually allows learning and memory.
Key questions which are addressed in this study:
How can specific newly synthesized endogenous proteins be visualized in situ? What are the neuron's abilities to locally synthesize and fully assemble AMPA receptor complexes?
How fast do different AMPA receptor subunits redistribute within neurons after synthesis?
Regulation of protein turnover allows cells to react to their environment and maintain homeostasis. Proteins can show different turnover rates in different tissue, but little is known about protein turnover in different brain cell types. We used dynamic SILAC to determine half-lives of over 5100 proteins in rat primary hippocampal cultures as well as in neuron-enriched and glia-enriched cultures ranging from <1 to >20 days. In contrast to synaptic proteins, membrane proteins were relatively shorter-lived and mitochondrial proteins were longer-lived compared to the population. Half-lives also correlate with protein functions and the dynamics of the complexes they are incorporated in. Proteins in glia possessed shorter half-lives than the same proteins in neurons. The presence of glia sped up or slowed down the turnover of neuronal proteins. Our results demonstrate that both the cell-type of origin as well as the nature of the extracellular environment have potent influences on protein turnover.
Cardiac sarcoidosis is a rare immunologic disease causing heart involvement in 5% of patients. Cardiac sarcoidosis may manifest clinically as a cardiomyopathy with impaired left ventricular (LV) function or as tachyarrhythmias or bradyarrhythmias. On autopsy, cardiac granulomas can be found in approximately 25% of patients. The most common location for granulomas and scars is the LV free wall, followed by the intraventricular septum, often with involvement of the conduction system. ...