Role of cyclic AMP in the control of cell-specific gene expression

Genes have to be expressed in specific cell types at appropriate times of development dependent on external signals. cAMP signaling occurs in all cells, thus raising the question of how this signal transduction pattern is integrated into mechanisms determining cell-specific gene expression. We have analyzed expression of the tyrosine aminotransferase gene as a model to study the basis of this cell type specificity of hormone induction. We found that cell-type-specific expression is generated by combined action of cAMP signal-dependent and liver cell-specific transcription factors. The interdependence of the cAMP response element and an element determining liver cell specificity enables a gene to respond to an ubiquitous signal in a cell-specific manner

The redundant target paradigm and its use as a blindsight-test : A meta-analytic study

Acknowledgements We would like to thank Malte Kühn for his invaluable help in conducting and rating the systematic literature research. Funding This research was supported by a grant from the German Research Foundation (Deutsche Forschungsgemeinschaft: DFG-SCHE 735/3-2).Peer reviewedPostprin

Die Auswirkungen der Tourismusindustrie auf die Existenzsicherung und dem damit verbundenen sozialen Wandel der lokalen Bevölkerung (Ticos/as) in Montezuma, Costa Rica

Durch die derzeit stark wachsende Tourismusindustrie findet ein großer Umbruch zwischen den Generationen der einheimischen Bevölkerung in Costa Rica statt, der zur Bildung von neuen sozialen und kulturellen Strukturen und der Verschiebung von Arbeitsaufteilung führt. Dadurch kommt es vermehrt zu Konflikten zwischen traditionellen landwirtschaftlichen Arbeiten und dem Aspekt der Ausbildung der Kinder, um diese für Zukunftsberufe in der wachsenden Tourismusindustrie durch Kenntnisse mehrerer Sprachen und der Computertechnologie mit besonderem Bezug zum Internet zu wappnen. Wie sich Globalisierungstendenzen in Form der Tourismusindustrie in Costa Rica und dem damit verbundenen Lebenswandel der einheimischen Bevölkerung auswirken, ist jedoch von der deutschsprachigen Literatur noch nicht hinreichend aufgearbeitet worden. Diese Arbeit soll den Einfluss einer rasch wachsenden Tourismusindustrie auf die Veränderung der Existenzsicherungsstrategien und insbesondere auf die traditionellen sozialen Strukturen und kulturellen Wertvorstellungen der indigenen Bevölkerung Costa Ricas aufzeigen. Nach einer kurzen demografischen und geschichtlichen Einführung in die Region, die weiterführend dazu dienen soll, die Entwicklung dieses modernen Schwellenlandes zu beleuchten, konzentriert sich die Diplomarbeit auf die soziale Situation vor Ort. Die Studie präsentiert einen Überblick der drei Faktoren des sozialen, kulturellen und ökonomischen Kapitals der lokalen Bevölkerung, welche durch den Tourismus ständigen dynamischen Veränderungen ausgesetzt sind. In diesem Zusammenhang wird deshalb die besondere Bedeutung von Anpassungsstrategien und der dadurch teilweise bedingten Aufgabe von autochthonen Traditionen herausgearbeitet. Die Studie besteht aus einem deskriptiven Teil, der die Grundvoraussetzungen des Landes und dessen Bevölkerung illustriert, sowie einer qualitativen Untersuchung mittels Interviews und Gesprächen, die durch quantitative Fragebögen abgerundet wird. In der Forschung wurden unter anderem die positiven Aspekte des Tourismus auf eine verbesserte Lebensqualität untersucht und auch potentielle negative Aspekte wie die Umweltproblematik und der Identitätsverlust der Costa RicanerInnen ausgelotet. Dabei konnten unterschiedliche Umgangsweisen mit dem florierenden Wirtschaftssektor Tourismus ausgemacht werden, die durch einen Generationskonflikt bestärkt werden konnten. (Autorenreferat)Working title: The impact of the tourism industry attending the subsistence hedging and the social alteration of the locals (Ticos/as) in Montezuma, Costa Rica. Through the currently strong expansion of the tourism industry there is a huge upheaval between the different generations of the local Costa Rican population, which manages new social and cultural structures, and work-sharing. Therefore, conflicts increase between the agricultural work and the aspect of educating the children, in order to prepare them for future-jobs in the growing tourism industry with knowledge of multiple languages, computer technology and special emphasis on the Internet. How globalization tendencies affect in the form of the tourism industry of Costa Rica and the therewith involved life-changes of the locals, is not adequately described in German literature. This paper should highlight the influence of the rapidly expanding tourism industry on the modification of the subsistence hedging – and, in particular, to the traditional social structures and cultural ideals of the Costa Rican locals. After a short demographic and historical introduction to the region, which continuative should serve to highlight the development of this modern and newly industrializing country, the thesis concentrates on the social situation of Montezuma. It presents an overview of three factors: social, cultural and economic capital of the locals, which is constantly exposed to unique changes due to tourism. In this context, the special meaning of the adaptive strategies and thereby partial conditional sacrifice of autochthonic traditions are going to be machined. The survey is composed of a descriptive part, which illustrates the basic requirements of Costa Rica and its population, and a qualitative analysis using interviews and tasks that through quantitative questionnaires is rounded. In addition, the analysis covers the positive aspects of tourism about a revised life-quality reviewed and also potentially negative aspects, like the environmental problem and the loss of identity of the Costa Ricans. Thereby it was possible to distinguish different ways of dealing with the flourishing tourism sector, which could be assured through the generation conflict. (Authors review

Enrichment and characterization of anaerobic phototrophic Fe(II)-oxidizing prokaryotes

Seit einigen Jahren gibt es die Theorie das Eisenoxidierenden Bakterien an der Entstehung der Banded Iron Formation (BIFs) beteiligt waren. Diese Gruppe von Bakterien benötigt keinen Sauerstoff fürs Leben und ist für die Reaktion von Fe(II) zu Fe(III) zuständig. Diese sogenannten anaeroben phototrophen Eisenoxidierenden Bakterien, die ihre Energie aus dem Sonnenlicht erhalten und CO2 fixieren, verwenden Fe(II) als Elektronendonor und bilden aus Fe(II) welches im Wasser gelöst ist, festes meist schlecht kristallisierte Eisenminerale wie Ferrihydrit. Diese Arbeit beschäftigt sich einerseits mit der ökologischen Verbreitung der Eisenoxidation durch phototrophe Eisenoxidierende Bakterien in Mitteleuropa. Andererseits mit der Isolierung und Charakterisierung eines Bakteriums welches für die Reaktion von Fe(II) zu Fe(III) zuständig ist. Zu diesem Zweck wurden 20 Proben aus unterschiedlichen Ökosystemen wie Eisenquellen, Teichen oder Flüssen genommen. Es wurden Wachstumsversuch und Eisenmessungen mittels der Ferrozin-Methode durchgeführt. Diese zeigten, dass die Oxidationen von Fe(II) in Anreicherungen durchschnittlich 10-21 Tage dauerten. Zusammenfassend konnten bei 17 von 20 Proben in einer oder mehreren Anreicherungsmethoden eine phototrophe Eisenoxidation festgestellt werden. Das Isolat ViMi23 wurde aufgrund seiner 16S rDNA den Rhodopseudomonas pseudopalustris DSM 123T zugeordnet. Die Zellen von Stamm ViMi23 zeigten eine keulenförmige Zellform und beinhalteten Bakteriochlorophyll a. Das Temperaturoptimum lag bei 25°C und das pH-Optimum bei 6.8. Das Isolat zeigte keinen Gärungsstoffwechsel, konnte aber Sauerstoff als Elektronenakzeptor im Dunkeln und andere Elektronendonatoren zum photoautotrophen oder photoheterotrophen Wachstum nutzen (unter anderem H2, Thiosulfat, S0, Acetat, Succinat, Propionat).Some decades ago a new theory of bacteria relevant for the formation of this iron stones were found. This new group of bacteria which do not need oxygen for life and could oxidize Fe(II) into Fe(III). The so-called Fe(II)-oxidizing anoxygenic phototrophic bacteria that obtain their energy from sunlight and fix CO2 using Fe(II) as a sole electron donor form solid, usually poorly crystallized iron minerals such as ferrihydrite. To evaluate the significance and spread of Fe(II) oxidation by phototrophic Fe(II)-oxidizing bacteria, samples were collected in middle Europe. In the end, one pure culture was obtained from one enrichment culture and characterized in detail. Growth experiments and iron measurements were conducted by applying the ferrozine-photometer method and showed an average of 10-21 days for iron oxidation. A relatively widespread occurrence of phototrophic iron oxidation was observed. Only three out of twenty samples showed no Fe(II)-oxidizing activity in the end. The isolate ViMi23 was a microaerophilic phototrophic Fe(II)-oxidizing bacterium with a growth temperature optimum near 25°C. The pH optimum for the growth of ViMi23 was approximately 6.8. Analysis of 16S rRNA gene sequences revealed an affiliation with Rhodopseudomonas pseudopalustris DSM 123T. Cells of strain ViMi23 were elongated to club-shaped and contained bacteriochlorophyll a. This isolate showed no fermentation metabolism, but was able to grow photoheterotrophically with many other substrates, for example, acetate, succinate or cysteine. Strain ViMi23 grew also photoautotrophically with H2 or sulfur compounds such as thiosulfate or elemental sulfur

Role of cyclic AMP in the control of cell-specific gene expression

Genes have to be expressed in specific cell types at appropriate times of development dependent on external signals. cAMP signaling occurs in all cells, thus raising the question of how this signal transduction pattern is integrated into mechanisms determining cell-specific gene expression. We have analyzed expression of the tyrosine aminotransferase gene as a model to study the basis of this cell type specificity of hormone induction. We found that cell-type-specific expression is generated by combined action of cAMP signal-dependent and liver cell-specific transcription factors. The interdependence of the cAMP response element and an element determining liver cell specificity enables a gene to respond to an ubiquitous signal in a cell-specific manner

Dynamics of Droplets Moving on Lubricated Polymer Brushes

Understanding the dynamics of drops on polymer-coated surfaces is crucial for optimizing applications such as self-cleaning materials or microfluidic devices. While the static and dynamic properties of deposited drops have been well characterised, a microscopic understanding of the underlying dynamics is missing. In particular, it is unclear how drop dynamics depends on the amount of uncrosslinked chains in the brush, because experimental techniques fail to quantify those. Here we use coarse-grained simulations to study droplets moving on a lubricated polymer brush substrate under the influence of an external body force. The simulation model is based on the many body dissipative particle dynamics (mDPD) method and designed to mimic a system of water droplets on polydimethylsiloxane (PDMS) brushes with chemically identical PDMS lubricant. In agreement with experiments, we find a sublinear power law dependence between the external force $F$ and the droplet velocity $v$, $F \propto v^\alpha$ with $\alpha <1$; however, the exponents differ ($\alpha \sim 0.6-0.7$ in simulations versus $\alpha \sim 0.25$ in experiments). With increasing velocity, the droplets elongate and the receding contact angle decreases, whereas the advancing contact angle remains roughly constant. Analyzing the flow profiles inside the droplet reveals that the droplets do not slide, but roll, with vanishing slip at the substrate surface. Surprisingly, adding lubricant has very little effect on the effective friction force between the droplet and the substrate, even though it has a pronounced effect on the size and structure of the wetting ridge, especially above the cloaking transition

Effective and successful quantification of leukemia-specific immune cells in AML patients’ blood or culture, focusing on intracellular cytokine and degranulation assays

Novel (immune) therapies are needed to stabilize remissions or the disease in AML. Leukemia derived dendritic cells (DCleu) can be generated ex vivo from AML patients’ blasts in whole blood using approved drugs (GM-CSF and PGE-1 (Kit M)). After T cell enriched, mixed lymphocyte culture (MLC) with Kit M pretreated (vs. untreated WB), anti-leukemically directed immune cells of the adaptive and innate immune systems were already shown to be significantly increased. We evaluated (1) the use of leukemia-specific assays [intracellular cytokine production of INFy, TNFa (INCYT), and degranulation detected by CD107a (DEG)] for a detailed quantification of leukemia-specific cells and (2), in addition, the correlation with functional cytotoxicity and patients’ clinical data in Kit M-treated vs. not pretreated settings. We collected whole blood (WB) samples from 26 AML patients at first diagnosis, during persisting disease, or at relapse after allogeneic stem cell transplantation (SCT), and from 18 healthy volunteers. WB samples were treated with or without Kit M to generate DC/DCleu. After MLC with Kit M-treated vs. untreated WB antigen-specific/anti-leukemic effects were assessed through INCYT, DEG, and a cytotoxicity fluorolysis assay. The quantification of cell subtypes was performed via flow cytometry. Our study showed: (1) low frequencies of leukemia-specific cells (subtypes) detectable in AML patients’ blood. (2) Significantly higher frequencies of (mature) DCleu generable without induction of blast proliferation in Kit M-treated vs. untreated samples. (3) Significant increase in frequencies of immunoreactive cells (e.g., non-naive T cells, Tprol) as well as in INCYT/DEG ASSAYS leukemia-specific adaptive—(e.g., B, T(memory)) or innate immune cells (e.g., NK, CIK) after MLC with Kit M-treated vs. untreated WB. The results of the intracellular production of INFy and TNFa were comparable. The cytotoxicity fluorolysis assay revealed significantly enhanced blast lysis in Kit M-treated vs. untreated WB. Significant correlations could be shown between induced leukemia-specific cells from several lines and improved blast lysis. We successfully detected and quantified immunoreactive cells at a single-cell level using the functional assays (DEG, INCYT, and CTX). We could quantify leukemia-specific subtypes in uncultured WB as well as after MLC and evaluate the impact of Kit M pretreated (DC/DCleu-containing) WB on the provision of leukemia-specific immune cells. Kit M pretreatment (vs. no pretreatment) was shown to significantly increase leukemia-specific IFNy and TNFa producing, degranulating cells and to improve blast-cytotoxicity after MLC. In vivo treatment of AML patients with Kit M may lead to anti-leukemic effects and contribute to stabilizing the disease or remissions. INCYT and DEG assays qualify to quantify potentially leukemia-specific cells on a single cell level and to predict the clinical course of patients under treatment

Interferon gamma secretion of adaptive and innate immune cells as a parameter to describe leukaemia-derived dendritic-cell-mediated immune responses in acute myeloid leukaemia in vitro

INTRODUCTION: Myeloid leukaemic blasts can be converted into leukaemia-derived dendritic cells (DCleu), characterised by the simultaneous expression of dendritic- and leukaemia-associated antigens, which have the competence to prime and enhance (leukaemia-specific) immune responses with the whole leukaemic antigen repertoire. To display and further specify dendritic cell (DC)- and DCleu-mediated immune responses, we analysed the interferon gamma (IFNy) secretion of innate and adaptive immune cells. METHODS: DC/DCleu were generated from leukaemic whole blood (WB) with (blast)modulatory Kit-I (granulocyte-macrophage colony-stimulating factor [GM-CSF] + Picibanil [OK-432]) and Kit-M (GM-CSF + prostaglandin E1) and were used to stimulate T cell-enriched immunoreactive cells. Initiated anti-leukaemic cytotoxicity was investigated with a cytotoxicity fluorolysis assay. Initiated IFNy secretion of T, NK, CIK, and iNKT cells was investigated with a cytokine secretion assay (CSA). IFNy positivity was additionally evaluated with an intracellular cytokine assay (ICA). Recent activation of leukaemia-specific cells was verified through addition of leukaemia-associated antigens (LAA; WT-1 and Prame) RESULTS: We found Kit-I and Kit-M competent to generate mature DC and DCleu from leukaemic WB without induction of blast proliferation. Stimulation of immunoreactive cells with DC/DCleu regularly resulted in an increased anti-leukaemic cytotoxicity and increased IFNy secretion of T, NK, and CIK cells, pointing to the significant role of DC/DCleu in leukaemia-specific alongside anti-leukaemic reactions. Interestingly, an addition of LAA did not further increase IFNy secretion, suggesting an efficient activation of leukaemia-specific cells. Here, both the CSA and ICA yielded comparable frequencies of IFNy-positive cells. Remarkably, the anti-leukaemic cytotoxicity positively correlated with the IFNy secretion in TCD3+, TCD4+, TCD8+, and NKCD56+ cells. CONCLUSION: Ultimately, the IFNy secretion of innate and adaptive immune cells appeared to be a suitable parameter to assess and monitor the efficacy of in vitro and potentially in vivo acute myeloid leukaemia immunotherapy. The CSA in this regard proved to be a convenient and reproducible technique to detect and phenotypically characterise IFNy-secreting cells. In respect to our studies on DC-based immunomodulation, we were able to display the potential of DC/DCleu to induce or improve leukaemia-specific and anti-leukaemic activity