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The Capital Markets Union-project of the European Commission aims for an increase of marketbased debt financing of small and medium-sized enterprises (SMEs), complementing bank lending. In this essay we argue that rather than focussing on pure non-bank lending, a reasonable mix of bankand market-based financing should be considered. Banks are said to have a comparative advantage in critical lending functions such as credit screening, debtor monitoring and debt renegotiation. All forms of lending require a persistent skin-in-the-game of critical players in order to be effective. The regulator should insist on full disclosure of skin-in-the-game, thereby improving capital allocation and reducing systemic risks.
Die Mittelalterabteilung des Liebieghauses unter der Leitung von Stefan Roller, stellt seit dem 6. Dezember seine neueste, spektakuläre Erwerbung vor. Das spätgotische (um 1470/75), noch original polychrom gefasste Christuskind wurde schon 2011 bei der Ausstellung "Niclaus Gerhaert. Der Bildhauer des Mittelalters" im Liebieghaus gezeigt und stammt aus Privatbesitz. ...
Bacteria are highly organized organisms which are able to adapt to and propagate under a multitude of environmental conditions. Propagation hereby requires reliable chromosome replication and segregation which has to occur cooperatively with other cellular processes such as transcription, translation or signaling. Several mechanisms were proposed for segregation of the Escherichia coli (E. coli) chromosome, for example a mitotic-like active segregation model or entropy-based passive chromosome segregation. Another segregation model suggests coupled transcription, translation and insertion of membrane proteins (termed "transertion"), which links the replicating chromosome (nucleoid) to the growing cell cylinder.
Fluorescence microscopy was widely used to provide evidence for a distinct segregation model. However, the dynamic nature of bacterial chromosomes, the small bacterial size and the optical resolution limit of ~ 200-300 nm impair unveiling the underlying mechanisms. With the emergence of super-resolution fluorescence microscopy techniques and advanced labeling methods, a new toolbox became available enabling scientists to visualize biomolecules and cellular processes in unprecedented detail. Single-molecule localization microscopy (SMLM) represents a set of super-resolution microscopy techniques which relies on the temporal separation of the fluorescence signal and detection of single fluorophores. Separation can be achieved using photoactivatable or -convertible fluorescent proteins (FPs) in photoactivated localization microscopy (PALM), photoswitchable organic dyes in direct stochastic optical reconstruction microscopy (dSTORM) or dynamically binding fluorescent probes in point accumulation for imaging in nanoscale topography (PAINT). In all these techniques, the fluorescence emission pattern of single fluorophores is spatially localized with nanometer-precision. An artificial image is finally reconstructed from the coordinates of all single fluorophores detected. This provides a spatial resolution of ~ 20 nm, which is perfectly suited to investigate cellular processes in bacteria. In this thesis, different SMLM techniques were applied to study fundamental processes in E. coli. This includes determination of protein copy numbers and distributions as well as the nanoscale organization of nucleic acids and lipids.
A novel labeling approach was applied and used for super-resolution imaging of the E. coli nucleoid. It is based on the incorporation of the modified thymidine analogue 5-ethynyl-2’- deoxyuridine (EdU) into the replicating chromosome. Azide-functionalized organic fluorophores can be covalently attached to the ethynyl group of incorporated EdU bases using a copper-catalyzed "click chemistry" reaction. Under the investigated growth condition, E. coli cells exhibited overlapping replication cycles, which is commonly referred to as multi-fork replication and enables cells to divide faster than they can replicate the entire chromosome. dSTORM imaging of such labeled nucleoids revealed chromosome features with diameters of 50 - 200 nm, representing highly condensed DNA filaments. Sorting single E. coli cells by length allowed visualizing structural changes of the nucleoid throughout the cell cycle. Replicating nucleoids segregated and expanded along the bacterial long axis, while constantly covering the entire width of the cell. Measuring cell and nucleoid length revealed a relative nucleoid expansion rate of 78 ± 6 %. At the same time, nucleoids populated 63 ± 8 % of the cell length, almost exclusively being localized to the cylindrical part of the cell. This value was hence normalized to the cylindrical fraction of the cell, yielding a value of 79 ± 10 % (nucleoid-populated fraction of the cell cylinder), which is in good agreement with the observed relative nucleoid expansion rate. These results therefore support a growth-mediated segregation model, in which the chromosome is anchored to the inner membrane and passively segregated into the prospective daughter cells upon cell growth. 3-dimensional dSTORM imaging of labeled nucleoids confirmed that compacted nucleoids helically wrap along the inner membrane. Similar results were obtained by imaging orthogonally aligned E. coli cells using a holographic optical tweezer approach.
In order to visualize particular proteins together with the nucleoid, several correlative imaging workflows were established, facilitating multi-color SMLM imaging in single E. coli cells. These workflows bypass prior limitations of SMLM, including destruction of FPs by reactive oxygen species in copper-catalyzed click reactions or incompatibility of PALM imaging with dSTORM imaging buffers. A sequential SMLM imaging routine was developed which is based on postlabeling and retrieval of previously imaged cells. Optimal imaging conditions can be maintained for each fluorophore, enabling to extract quantitative information from PALM measurements while correlating the protein distribution to the nucleoid ultrastructure within the highly resolved cell envelope. Applying this workflow to an E. coli strain carrying a chromosomal rpoC - photoactivatable mCherry (PAmCh) fusion, transcribing RNA polymerase (RNAP) was found to be localized on the surface of nucleoids, where active genes are exposed towards the cytosol. During growth in nutrient-rich medium, the majority of RNAP molecules was bound to the chromosome, thus ensuring that the RNAP pool is equally distributed to the daughter cells upon cell division. This work represented the first triple-color SMLM study performed in E. coli cells. ...
Very few people doubt that it is a fundamental demand of justice that members of legal-political normative orders ought to have legal rights that define their basic standing as subjects of such an order. But when it comes to the concrete understanding of such rights, debates abound. What is the nature of these rights – are they an expression of the sovereign will of individuals, or are they based on important human interests? How should these rights be justified – do they have a particular moral ground, and if so, only one or many?
Box C/D snoRNAs are known to guide site-specific ribose methylation of ribosomal RNA. Here, we demonstrate a novel and unexpected role for box C/D snoRNAs in guiding 18S rRNA acetylation in yeast. Our results demonstrate, for the first time, that the acetylation of two cytosine residues in 18S rRNA catalyzed by Kre33 is guided by two orphan box C/D snoRNAs–snR4 and snR45 –not known to be involved in methylation in yeast. We identified Kre33 binding sites on these snoRNAs as well as on the 18S rRNA, and demonstrate that both snR4 and snR45 establish extended bipartite complementarity around the cytosines targeted for acetylation, similar to pseudouridylation pocket formation by the H/ACA snoRNPs. We show that base pairing between these snoRNAs and 18S rRNA requires the putative helicase activity of Kre33, which is also needed to aid early pre-rRNA processing. Compared to yeast, the number of orphan box C/D snoRNAs in higher eukaryotes is much larger and we hypothesize that several of these may be involved in base-modifications.
Am Fachbereich Medizin und dem Klinikum der Johann Wolfgang-Goethe-Universität Frankfurt existierten bereits seit 2002 mehrere einzelne medizindidaktische Kurse. Diese Aktivitäten wurden 2011 strukturiert, ein umfassendes Kursangebot, das das breite Spektrum an Themen rund um die Lehre abdeckt, wurde aufgebaut und unter dem Dach der Frankfurter Arbeitsstelle für Medizindidaktik (FAM) am Fachbereich institutionalisiert. Folgende Faktoren waren für die erfolgreiche Umsetzung ausschlaggebend: vorhandene Programme in anderen Bundesländern (v.a. Baden-Württemberg, Nordrhein-Westfalen) mit entsprechenden Vorgaben, die Unterstützung der Studiendekane, die Verankerung der Teilnahme an medizindidaktischen Kursen in der Habilitationsordnung sowie eine kritische Masse von an der Lehre interessierten Mitarbeiterinnen und Mitarbeitern. Kernelemente des Angebots sind ein Basiskurs für alle neu eingestellten wissenschaftlichen Angestellten mit Lehrverpflichtung und ein modularer Aufbau des Programms, der individuellen Präferenzen bzw. Erfordernissen entgegen kommt. Gleichwohl die Teilnahme am Kursprogramm überwiegend verpflichtend erfolgt, zeigt sich eine hohe Zufriedenheit und ein nachhaltiger Wissenszuwachs bei den Kursteilnehmerinnen und Kursteilnehmern.
Phytotoxic dioxolanones from Guignardia bidwellii can be described as potential virulence factors which cause the formation of lesions upon an infection by G. bidwellii. The toxin guignardic acid was found in planta of G. bidwellii-infected Vitis vinifera leaves, whereas no phytotoxic dioxolanones were detected in uninfected leaf material. Secondary metabolism analyses of further phytopathogenic fungi from the genus Guignardia led to the observation that all species investigated can produce the phytotoxins known from G. bidwellii. In addition to these studies, it was demonstrated that phenguignardic acid is biosynthetically derived from two molecules of phenylalanine and that phenylalanine is a key precursor in the biosynthesis of the two other phytotoxins – alaguignardic acid and guignardic acid.
Tumor cells frequently overexpress heat shock protein 70 (Hsp70) and present it on their cell surface, where it can be recognized by pre‐activated NK cells. In our retrospective study the expression of Hsp70 was determined in relation to tumor‐infiltrating CD56+ NK cells in formalin‐fixed paraffin embedded (FFPE) tumor specimens of patients with SCCHN (N = 145) as potential indicators for survival and disease recurrence. All patients received radical surgery and postoperative cisplatin‐based radiochemotherapy (RCT). In general, Hsp70 expression was stronger, but with variable intensities, in tumor compared to normal tissues. Patients with high Hsp70 expressing tumors (scores 3–4) showed significantly decreased overall survival (OS; p = 0.008), local progression‐free survival (LPFS; p = 0.034) and distant metastases‐free survival (DMFS; p = 0.044), compared to those with low Hsp70 expression (scores 0–2), which remained significant after adjustment for relevant prognostic variables. The adverse prognostic value of a high Hsp70 expression for OS was also observed in patient cohorts with p16‐ (p = 0.001), p53‐ (p = 0.0003) and HPV16 DNA‐negative (p = 0.001) tumors. The absence or low numbers of tumor‐infiltrating CD56+ NK cells also correlated with significantly decreased OS (p = 0.0001), LPFS (p = 0.0009) and DMFS (p = 0.0001). A high Hsp70 expression and low numbers of tumor‐infiltrating NK cells have the highest negative predictive value (p = 0.00004). In summary, a strong Hsp70 expression and low numbers of tumor‐infiltrating NK cells correlate with unfavorable outcome following surgery and RCT in patients with SCCHN, and thus serve as negative prognostic markers.
In der vorliegenden Studie wurden sieben verschiedene Biomarker (Survivin, Ki-S2, EGFR, Her2/neu, PTEN, p53, OSF-2) von Plattenepithelkarzinomen der Mundhöhle und des anterioren Oropharynx bezüglich ihres Expressionsverhaltens vor und nach Applikation einer intraarteriellen Induktionschemotherapie mit 150mg/m² Cisplatin und im Hinblick auf einen möglichen Zusammenhang des Expressionsverhaltens mit dem Chemotherapieresponse untersucht.
Mit Hilfe der TMA-Technologie wurde in Gewebeproben von 41 Patienten, welche am genannten Krebs erkrankt waren, die Expressionsraten immunhistochemisch bestimmt. Die Behandlung der Patienten erfolgte im Rahmen eines multimodalen Therapiekonzepts in der Klinik für Mund-, Kiefer- und Plastische Gesichtschirurgie am Klinikum der Johann Wolfgang Goethe-Universität in Frankfurt am Main. Alle Patienten hatten eine intraarterielle Induktionschemotherapie erhalten gefolgt von einer chirurgischen Intervention. Spätestens nach sechs Wochen erfolgte die adjuvante Bestrahlung beziehungsweise Radiochemotherapie (Maximalvariante). 56% der Patienten erhielten die Maximalvariante.
Die allgemeine pathologische Ansprechrate nach intraarterieller Induktion lag bei 39% (2%= pCR, 37%= pPR). 59% der Patienten zeigten kein Ansprechen auf die Induktion (pSD) und 2% zeigten eine Progression (pPD). Die Expressionsraten der einzelnen Biomarker wurden jeweils vor und nach intraarterieller Induktionschemotherapie bestimmt. Die statistische Analyse erfolgte univariat mittels Wilcoxon-Mann-Whitney-U-Test und Wilcoxon-matched-pairs-Test. Für Survivin, Ki-S2, OSF-2 und EGFR konnten signifikante Unterschiede nach Induktion verzeichnet werden, die Expressionsrate stieg für Survivin Kern (p= 0,0001), OSF-2 (OSF-2 Zytoplasma, p= 0,0067; OSF-2 Membran, p= 0,0001) und EGFR (p= 0,039) signifikant an. Für Ki-S2 nahm die Expressionsrate signifikant ab (p= 0,001).
In der Vergleichsgruppe Responder versus Non-Responder konnten sowohl in der diagnostischen Primärtumorbiopsie als auch im OP-Präparat des Primärtumors nach Induktion keine signifikanten Unterschiede zwischen Respondern und Non-Respondern in den Expressionsraten festgestellt werden. Für Survivin Zytoplasma lagen die Expressionsraten für die Responder-Patienten vor und nach Induktion im oberen Bereich. Für PTEN konnte bei 75% der Patienten ein Expressionsverlust verzeichnet werden. Damit konnte in der hier durchgeführten Studie kein Biomarker detektiert werden, welcher für eine signifikante Vorhersage zur Responserate herangezogen werden könnte.
Die Änderung der Expressionsraten von Biomarkern bei oralen und oropharyngealen Plattenepithelkarzinomen nach intraarterieller Induktionschemotherapie ist ein Befund, der an ähnliche Beobachtungen nach neoadjuvanter Chemotherapie z. B. beim Mammakarzinom anknüpft und darum weiter verfolgt werden sollte.