PD Trafficking of Potato Leaf Roll Virus Movement Protein in Arabidopsis Depends on Site-specific Protein Phosphorylation

Many plant viruses encode for specialized movement proteins (MP) to facilitate passage of viral material to and through plasmodesmata (PD). To analyze intracellular trafficking of potato leaf roll virus (PLRV) movement protein (MP17) we performed GFP fusion experiments with distinct deletion variants of MP17. These studies revealed that the C-terminus of MP17 is essential but not sufficient for PD targeting. Interestingly, fusion of GFP to three C-terminal MP17 deletion variants resulted in the accumulation of GFP in chloroplasts. This indicates that MP17 harbors hidden plastid targeting sequences. Previous studies showed that posttranslational protein phosphorylation influences PD targeting of MP and virus spread. Analysis of MP17-derived phospho-peptides by mass spectrometry revealed four phosphorylated serine residues (S71, S79, S137, and S140). Site-directed mutagenesis of S71/S79 and S137/S140 showed that the C-terminal serine residues S137/S140 are dispensable for PD targeting. However, exchange of S71/S79 to A71/A79 abolished PD targeting of the mutated MP17 protein. To mimic phosphorylation of S71/S79 both amino acids were substituted by aspartic acid. The resulting D71/D79 variant of MP17 was efficiently targeted to PD. Further deletion analysis showed that PD targeting of MP17 is dependent on the C-terminus, phosphorylation of S71 and/or S79 and a N-terminal domain

Grenzflächenausbildung zwischen LiNbO3 (LiTaO3) und Barriereschichten für den Einsatz bei Metallisierungssystemen für SAW-Strukturen

Diese Dissertation beschäftigt sich mit der Grenzflächenausbildung von dünnen Tantal- und Titan-basierenden Schichten zu den piezoelektrischen Substratmaterialien Lithiumniobat sowie Lithiumtantalat, als Teil eines Schichtstapels für die Metallisierung akustischer Oberflächenbauelemente. Ziel ist es das grundlegende Verständnis für die chemischen Wechselwirkungen beim Aufwachsen der Schichten, ihrer thermischen und zeitlichen Stabilität sowie ihrer Effekte auf das Schichtwachstum einer Deckschicht bestehend aus Aluminium zu gewinnen. Ein Schwerpunkt war die Präparation der Substratoberflächen hinsichtlich einer Oberflächenreinigung und -modifikation. Zu diesem Zweck wurden neben verschiedenen Standard-Verfahren auch eine eigens angefertigte plasmagestützte Oberflächenbehandlung systematisch analysiert. Auf derart präparierten Substraten fanden im Folgenden die Schichtabscheidung und die Analyse des Schichtwachstums, hauptsächlich mit winkelaufgelöster Photoelektronenspektroskopie, statt. Anhand von thermischen Belastungen sowie zeitlicher Veränderungen der Schichten im Vakuum konnten grundlegende Aussagen zur Stabilität der Grenzflächen gewonnen werden. Zur Komplettierung des Schichtstapels wurden auf ausgewählten Substrat-Schicht Kombinationen das Wachstum von Aluminiumschichten hinsichtlich ihrer unterschiedlicher Texturbildung analysiert und Aussagen zur Relevanz chemischer Ursachen getroffen.This dissertation addresses the interface formation between thin Tantalum and Titanium based layers onto the piezoelectric substrate materials Lithiumniobate and Lithiumtantalate as part of a metallisation stack for surface acoustic wave devices. The goal is to extend the fundamental knowledge of chemical interactions during layer growth, its thermal and temporal stability plus its effects on the layer growth of an Aluminium cover layer. One focus lies on the preparation of the substrate surfaces for cleaning and modification purpose. For this, besides standard procedures a specially built plasma-based device was systematically evaluated for surface treatment. The following layer deposition was then implemented onto these prepared substrate surfaces and mainly analysed by angle-resolved photoelectron spectroscopy. By the means of thermal load and temporal alteration of the layers in vacuum essential knowledge about the interface stability was gained. For the completion of a whole layer stack selected substrate-layer combinations were covered with Aluminum and its layer growth was analysed with respect to the different formation of texture and its potential chemical cause

Midlatitude ClO during the maximum atmospheric chlorine burden : in situ balloon measurements and model simulations

Chlorine monoxide (ClO) plays a key role in stratospheric ozone loss processes at midlatitudes. We present two balloonborne in situ measurements of ClO conducted in northern hemisphere midlatitudes during the period of the maximum of total inorganic chlorine loading in the atmosphere. Both ClO measurements were conducted on board the TRIPLE balloon payload, launched in November 1996 in Le´on, Spain, and in May 1999 in Aire sur l’Adour, France. For both flights a ClO daylight and night time vertical profile could be derived over an altitude range of approximately 15–31 km. ClO mixing ratios are compared to model simulations performed with the photochemical box model version of the Chemical Lagrangian Model of the Stratosphere (CLaMS). Simulations along 24-h backward trajectories were performed to study the diurnal variation of ClO in the midlatitude lower stratosphere. Model simulations for the flight launched in Aire sur l’Adour 1999 show a good agreement with the ClO measurements. For the flight launched in Le´on 1996, a similar good agreement is found, except at around ~ 650 K potential temperature (~26km altitude). However, a tendency is found that for solar zenith angles greater than 86°–87° the simulated ClO mixing ratios substantially overestimate measured ClO by approximately a factor of 2.5 or more for both flights. Therefore we conclude that no indication can be deduced from the presented ClO measurements that substantial uncertainties exist in midlatitude chlorine chemistry of the stratosphere. An exception is the situation at solar zenith angles greater than 86°–87° where model simulations substantial overestimate ClO observations

A Novel Multi Slit X-Ray Backscatter Camera Based on Synthetic Aperture Focusing

A special slit collimator was developed earlier for fast acquisition of X-ray back scatter images. The design was based on a twisted slit design (ruled surfaces) in a Tungsten block to acquire backscatter images. The comparison with alternative techniques as the flying spot and the coded aperture pin hole technique could not prove the expected higher contrast sensitivity. In analogy to the coded aperture technique, a novel multi slit camera was designed and tested. Several twisted slits were parallelly arranged in a metal block. The CAD design of different multi-slit cameras was evaluated and optimized by the computer simulation packages aRTist and McRay. The camera projects a set of equal images per slit to the digital detector array, which are overlaying each other. Afterwards, the aperture is corrected based on a deconvolution algorithm to focus the overlaying projections into a single representation of the object. Furthermore, a correction of the geometrical distortions due to the slit geometry is performed. The expected increase of the contrast-to-noise ratio is proportional to the square root of the number of parallel slits in the camera. However, additional noise has to be considered originating from the deconvolution operation. The slit design, functional principle, and the expected limits of this technique will be discussed

Unterrichtsprojekt "(Anti-)Rassismus - Wir begeben uns auf eine Zeitreise!"

Chelsea Vogel, Uwe Hoßfeld und Karl Porges fragen, wie sich (Anti-)Rassismus im Biologieunterricht behandeln lässt und bieten die Idee, mithilfe eines Workbooks die Lernenden auf eine Zeitreise mitzunehmen. (DIPF/Orig.

Enhancement of fluorescent properties of near-infrared dyes using clickable oligoglycerol dendrons

Near-infrared (NIR) fluorescent dyes are gaining increased attention due to their potential to serve as molecular probes for in vivo imaging. Here, we demonstrate that oligoglycerol dendrons effectively enhance the fluorescence properties of an NIR dye by increasing the solubility in water and the prevention of aggregate formation. First- and second-generation oligoglycerol dendrons were conjugated to an NIR dye via a dipolar-cycloaddition (click) reaction. The two new dye conjugates exhibited enhanced NIR fluorescent emission and considerably higher fluorescent quantum yields than the dye alone. The high photostability measured for one of the oligoglycerol-linked dyes, in comparison to commonly used fluorogenic dyes such as Cy5 and Cy7, was validated using fluorescence microscopy of macrophages

Prof. Dr. med. Bernhard Riedel (1846-1916) und seine Leistungen auf dem Gebiet der Abdominalchirurgie: eine Analyse seiner Jenaer Operationstagebücher im Zeitraum von 1888 bis 1910

Mit der Entdeckung der Narkose im Jahre 1846 begann in der Medizin eine neue Ära, der ein enormer Aufschwung, insbesondere in der Chirurgie, in der zweiten Hälfte des 19. Jahrhunderts folgte. Im gleichen Jahr dieses Wendepunktes wurde auch Bernhard Carl Ludwig Moritz Riedel am 18. September in Laage in Mecklenburg geboren. In der vorliegenden Dissertation steht als Beitrag zur Geschichte der Medizinischen Fakultät Jenas Bernhard Riedels Leben und Wirken im Mittelpunkt. Dabei wird insbesondere die Zeit seines Chirurgischen Ordinariats an der Universität Jena von 1888 bis 1910 einschließlich seiner Lehrtätigkeit und Schüler wie Heinrich Haeckel (geb. 1859) oder Wilhelm Röpke (1873-1945) thematisiert. Als Zeugnisse seines Schaffens in Jena sind zwölf Bände seiner Operationstagebücher erhalten geblieben, die der Friedrich-Schiller-Universität Jena durch Riedels Nachkommen im April 1998 zur wissenschaftlichen Auswertung übergeben wurden. Die Analyse dieser Tagebücher bildet neben der Biografie Riedels einen weiteren Schwerpunkt der Arbeit. Abschließend wurden daraus Fallbeispiele ausgewählt, zu denen Bezüge aus Riedels wissenschaftlichen Schriften hergestellt werden. Bei der Auseinandersetzung mit dem Leben und Schaffen von Bernhard Riedel lernt man ihn als vielseitigen und ehrgeizigen Chirurgen kennen, durch dessen Ordinariat die Alma mater Jenensis über die thüringischen Grenzen hinaus Anerkennung erlangen konnte

The Thrombopoietin Receptor Agonist Eltrombopag Inhibits Human Cytomegalovirus Replication Via Iron Chelation

The thrombopoietin receptor agonist eltrombopag was successfully used against human cytomegalovirus (HCMV)-associated thrombocytopenia refractory to immunomodulatory and antiviral drugs. These effects were ascribed to the effects of eltrombopag on megakaryocytes. Here, we tested whether eltrombopag may also exert direct antiviral effects. Therapeutic eltrombopag concentrations inhibited HCMV replication in human fibroblasts and adult mesenchymal stem cells infected with six different virus strains and drug-resistant clinical isolates. Eltrombopag also synergistically increased the anti-HCMV activity of the mainstay drug ganciclovir. Time-of-addition experiments suggested that eltrombopag interfered with HCMV replication after virus entry. Eltrombopag was effective in thrombopoietin receptor-negative cells, and the addition of Fe3+ prevented the anti-HCMV effects, indicating that it inhibits HCMV replication via iron chelation. This may be of particular interest for the treatment of cytopenias after hematopoietic stem cell transplantation, as HCMV reactivation is a major reason for transplantation failure. Since therapeutic eltrombopag concentrations are effective against drug-resistant viruses, and synergistically increase the effects of ganciclovir, eltrombopag is also a drug-repurposing candidate for the treatment of therapy-refractory HCMV disease

Disturbing-free determination of yeast concentration in DI water and in glucose using impedance biochips

Deionized water and glucose without yeast and with yeast (Saccharomyces cerevisiae) of optical density OD600 that ranges from 4 to 16 has been put in the ring electrode region of six different types of impedance biochips and impedance has been measured in dependence on the added volume (20, 21, 22, 23, 24, 25 µL). The measured impedance of two out of the six types of biochips is strongly sensitive to the addition of both liquid without yeast and liquid with yeast and modelled impedance reveals a linear relationship between the impedance model parameters and yeast concentration. The presented biochips allow for continuous impedance measurements without interrupting the cultivation of the yeast. A multiparameter fit of the impedance model parameters allows for determining the concentration of yeast (cy) in the range from cy = 3.3 × 107 to cy = 17 × 107 cells/mL. This work shows that independent on the liquid, i.e., DI water or glucose, the impedance model parameters of the two most sensitive types of biochips with liquid without yeast and with liquid with yeast are clearly distinguishable for the two most sensitive types of biochips