@phdthesis{Kirscher2014, author = {Kirscher, Lorenz}, title = {Melanogene rekombinante Vaccinia-Viren als diagnostisches und therapeutisches Agenz zur Tumorbehandlung}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112074}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2014}, abstract = {Die g{\"a}ngigen therapeutischen Behandlungsmethoden f{\"u}r die verschiedensten Krebserkrankungen zeigen nach wie vor M{\"a}ngel bez{\"u}glich der Effizienz sowie zahlreiche Nebenwirkungen w{\"a}hrend und nach der Behandlung. Maßgeblich f{\"u}r diese Defizite ist die teilweise geringe Sensitivit{\"a}t der meisten konventionellen diagnostischen Systeme und damit einhergehend die oftmals zu sp{\"a}te Identifikation entarteter Gewebsbereiche. Zur L{\"o}sung dieser Problematik bieten onkolytische Vaccinia-Viren einen Ansatz, sowohl die Effizienz der Therapie wie auch die Diagnostik zu verbessern. In beiden F{\"a}llen sind die Tumorzell-spezifische Vermehrung der Viren und die M{\"o}glichkeit entscheidend, die Viren als Vektorsystem zur Expression therapeutischer oder diagnostischer Fremdgenkassetten zu nutzen. Um ein auf Vaccinia-Virus-basierendes Reportersystem zum diagnostischen Nachweis von Krebszellen mittels Tiefengewebs-Tomographie bereit zu stellen, wurden die f{\"u}r die murine Tyrosinase (mTyr) und das Tyrosinase-Helferprotein 1 (Tyrp1) kodierenden Gene in das Genom eines onkolytischen Vaccinia-Virus inseriert. Die Tyrosinase ist das Schl{\"u}sselenzym der Melaninsynthese. Bereits die solit{\"a}re Expression der Tyrosinase f{\"u}hrt in der transformierten Zelle zur Melaninproduktion. Das Tyrosinase-Helferprotein 1 ist an der Prozessierung und Stabilisierung der Tyrosinase beteiligt. Bereits in verschiedenen Studien konnte gezeigt werden, dass Melanin als Reportermolek{\"u}l f{\"u}r die Magnetresonanz sowie f{\"u}r die multispektrale optoakustische Tomographie einsetzbar ist. Es wurde deswegen angestrebt, die Kombination aus dem therapeutischen Potential des onkolytischen Vaccinia-Virus und der diagnostischen Anwendung des Melanins als Reporter auszunutzen. S{\"a}mtliche in dieser Arbeit aufgef{\"u}hrten rekombinanten Vaccinia-Viren (rVACV) wurden von der Firma Genelux Corporation zur Verf{\"u}gung gestellt und in dieser Arbeit hinsichtlich der therapeutischen Effizienz und des diagnostischen Potentials untersucht. In ersten Zellkultur-Versuchen wurde anhand verschiedener konstitutiv melanogener rVACV-Konstrukte festgestellt, dass die Kombination aus dem Vaccinia-Virus-spezifischen synthetic early/late Promotor und dem Enzym Tyrosinase (GLV-1h327) bzw. den Enzymen Tyrosinase und Tyrosinase-Helferprotein 1 (GLV-1h324) die h{\"o}chste Melaninsynthese-Rate zeigte. Anschließend wurde mittels der Bestimmung der spektralen Absorption und der Enzymaktivit{\"a}t der viral kodierten Melanin synthetisierenden Enzyme sowie mikroskopischer Analysen gezeigt, dass es mit diesen auf 8 Vaccinia-Virus-basierenden melanogenen Reportersystemen m{\"o}glich ist, die Melaninsynthese in nicht-melanogenen Zellen zu induzieren. Anhand elektronenmikroskopischer Untersuchungen in Zellkultur und ex vivo konnte gezeigt werden, dass die nach rVACV-Infektion stattfindende Melaninsynthese in den Lysosomen der Wirtszelle abl{\"a}uft. Eine Analyse der atomaren Zusammensetzung des viral vermittelten Melanins ergab, dass es sich um eine Mischform aus Eu- und Ph{\"a}omelanin handelt. Dieser Melanin-Mix {\"a}hnelte dem Melanin aus Haut und Augen, jedoch lagen an Melanin-gebundene Metallionen in erh{\"o}htem Maß vor...}, subject = {Melanin}, language = {de} } @phdthesis{LuiblneeHermann2014, author = {Luibl [n{\´e}e Hermann], Christiane}, title = {The role of the neuropeptides NPF, sNPF, ITP and PDF in the circadian clock of Drosophila melanogaster}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-93796}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2014}, abstract = {Organisms have evolved endogenous clocks which allow them to organize their behavior, metabolism and physiology according to the periodically changing environmental conditions on earth. Biological rhythms that are synchronized to daily changes in environment are governed by the so-called circadian clock. Since decades, chronobiologists have been investigating circadian clocks in various model organisms including the fruitfly Drosophila melanogaster, which was used in the present thesis. Anatomically, the circadian clock of the fruitfly consists of about 150 neurons in the lateral and dorsal protocerebrum, which are characterized by their position, morphology and neurochemistry. Some of these neurons had been previously shown to contain either one or several neuropeptides, which are thought to be the main signaling molecules used by the clock. The best investigated of these neuropeptides is the Pigment Dispersing Factor (PDF), which had been shown to constitute a synchronizing signal between clock neurons as well as an output factor of the clock. In collaboration with various coworkers, I investigated the roles of three other clock expressed neuropeptides for the generation of behavioral rhythms and the partly published, partly unpublished data are presented in this thesis. Thereby, I focused on the Neuropeptide F (NPF), short Neuropeptide F (sNPF) and the Ion Transport Peptide (ITP). We show that part of the neuropeptide composition within the clock network seems to be conserved among different Drosophila species. However, the PDF expression pattern in certain neurons varied in species deriving from lower latitudes compared to higher latitudes. Together with findings on the behavioral level provided by other people, these data suggest that different species may have altered certain properties of their clocks - like the neuropeptide expression in certain neurons - in order to adapt their behavior to different habitats. We then investigated locomotor rhythms in Drosophila melanogaster flies, in which neuropeptide circuits were genetically manipulated either by cell ablation or RNA interference (RNAi). We found that none of the investigated neuropeptides seems to be of equal importance for circadian locomotor rhythms as PDF. PDF had been previously shown to be necessary for rhythm maintenance in constant darkness (DD) as well as for the generation of morning (M) activity and for the right phasing of the evening (E) activity in entrained conditions. We now demonstrate that NPF and ITP seem to promote E activity in entrained conditions, but are clearly not the only factors doing so. In addition, ITP seems to reduce nighttime activity. Further, ITP and possibly also sNPF constitute weak period shortening components in DD, thereby opposing the effect of PDF. However, neither NPF or ITP, nor sNPF seem to be necessary in the clock neurons for maintaining rhythmicity in DD. It had been previously suggested that PDF is released rhythmically from the dorsal projection terminals. Now we discovered a rhythm in ITP immunostaining in the dorsal projection terminals of the ITP+ clock neurons in LD, suggesting a rhythm in peptide release also in the case of ITP. Rhythmic release of both ITP and PDF seems to be important to maintain rhythmic behavior in DD, since constantly high levels of PDF and ITP in the dorsal protocerebrum lead to behavioral arrhythmicity. Applying live-imaging techniques we further demonstrate that sNPF acts in an inhibitory way on few clock neurons, including some that are also activated by PDF, suggesting that it acts as signaling molecule within the clock network and has opposing effects to PDF. NPF did only evoke very little inhibitory responses in very few clock neurons, suggesting that it might rather be used as a clock output factor. We were not able to apply the same live-imaging approach for the investigation of the clock neuron responsiveness to ITP, but overexpression of ITP with various driver lines showed that the peptide most likely acts mainly in clock output pathways rather than inter-clock neuron communication. Taking together, I conclude that all investigated peptides contribute to the control of locomotor rhythms in the fruitfly Drosophila melanogaster. However, this control is in most aspects dominated by the actions of PDF and rather only fine-tuned or complemented by the other peptides. I assume that there is a high complexity in spatial and temporal action of the different neuropeptides in order to ensure correct signal processing within the clock network as well as clock output.}, subject = {Taufliege}, language = {en} } @article{ChenGerber2014, author = {Chen, Yi-chun and Gerber, Bertram}, title = {Generalization and discrimination tasks yield concordant measures of perceived distance between odours and their binary mixtures in larval Drosophila}, series = {The Journal of Experimental Biology}, volume = {217}, journal = {The Journal of Experimental Biology}, number = {12}, doi = {10.1242/jeb.100966}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121625}, pages = {2071-7}, year = {2014}, abstract = {Similarity between odours is notoriously difficult to measure. Widely used behavioural approaches in insect olfaction research are cross-adaptation, masking, as well as associative tasks based on olfactory learning and the subsequent testing for how specific the established memory is. A concern with such memory-based approaches is that the learning process required to establish an odour memory may alter the way the odour is processed, such that measures of perception taken at the test are distorted. The present study was therefore designed to see whether behavioural judgements of perceptual distance are different for two different memory-based tasks, namely generalization and discrimination. We used odour-reward learning in larval Drosophila as a study case. In order to challenge the larvae's olfactory system, we chose to work with binary mixtures and their elements (1-octanol, n-amyl acetate, 3-octanol, benzaldehyde and hexyl acetate). We determined the perceptual distance between each mixture and its elements, first in a generalization task, and then in a discrimination task. It turns out that scores of perceptual distance are correlated between both tasks. A re-analysis of published studies looking at element-to-element perceptual distances in larval reward learning and in adult punishment learning confirms this result. We therefore suggest that across a given set of olfactory stimuli, associative training does not grossly alter the pattern of perceptual distances.}, language = {en} } @article{StefanovicBarnettvanDuijvenbodenetal.2014, author = {Stefanovic, Sonia and Barnett, Phil and van Duijvenboden, Karel and Weber, David and Gessler, Manfred and Christoffels, Vincent M.}, title = {GATA-dependent regulatory switches establish atrioventricular canal specificity during heart development}, series = {Nature Communications}, volume = {5}, journal = {Nature Communications}, number = {3680}, issn = {2041-1723}, doi = {10.1038/ncomms4680}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121437}, year = {2014}, abstract = {The embryonic vertebrate heart tube develops an atrioventricular canal that divides the atrial and ventricular chambers, forms atrioventricular conduction tissue and organizes valve development. Here we assess the transcriptional mechanism underlying this localized differentiation process. We show that atrioventricular canal-specific enhancers are GATA-binding site-dependent and act as switches that repress gene activity in the chambers. We find that atrioventricular canal-specific gene loci are enriched in H3K27ac, a marker of active enhancers, in atrioventricular canal tissue and depleted in H3K27ac in chamber tissue. In the atrioventricular canal, Gata4 activates the enhancers in synergy with Bmp2/Smad signalling, leading to H3K27 acetylation. In contrast, in chambers, Gata4 cooperates with pan-cardiac Hdac1 and Hdac2 and chamber-specific Hey1 and Hey2, leading to H3K27 deacetylation and repression. We conclude that atrioventricular canal-specific enhancers are platforms integrating cardiac transcription factors, broadly active histone modification enzymes and localized co-factors to drive atrioventricular canal-specific gene activity.}, language = {en} } @article{McCarthyMooreKraussetal.2014, author = {McCarthy, Michael A. and Moore, Alana L. and Krauss, Jochen and Morgan, John W. and Clements, Christopher F.}, title = {Linking Indices for Biodiversity Monitoring to Extinction Risk Theory}, series = {Conservation Biology}, volume = {28}, journal = {Conservation Biology}, number = {6}, doi = {10.1111/cobi.12308}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121218}, pages = {1575-83}, year = {2014}, abstract = {Biodiversity indices often combine data from different species when used in monitoring programs. Heuristic properties can suggest preferred indices, but we lack objective ways to discriminate between indices with similar heuristics. Biodiversity indices can be evaluated by determining how well they reflect management objectives that a monitoring program aims to support. For example, the Convention on Biological Diversity requires reporting about extinction rates, so simple indices that reflect extinction risk would be valuable. We developed 3 biodiversity indices that are based on simple models of population viability that relate extinction risk to abundance. We based the first index on the geometric mean abundance of species and the second on a more general power mean. In a third index, we integrated the geometric mean abundance and trend. These indices require the same data as previous indices, but they also relate directly to extinction risk. Field data for butterflies and woodland plants and experimental studies of protozoan communities show that the indices correlate with local extinction rates. Applying the index based on the geometric mean to global data on changes in avian abundance suggested that the average extinction probability of birds has increased approximately 1\% from 1970 to 2009.}, language = {en} } @article{ZhanStanciauskasStigloheretal.2014, author = {Zhan, Hong and Stanciauskas, Ramunas and Stigloher, Christian and Dizon, Kevin K. and Jospin, Maelle and Bessereau, Jean-Luis and Pinaud, Fabien}, title = {In vivo single-molecule imaging identifies altered dynamics of calcium channels in dystrophin-mutant C. elegans}, series = {Nature Communications}, volume = {5}, journal = {Nature Communications}, number = {4974}, doi = {10.1038/ncomms5974}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121125}, year = {2014}, abstract = {Single-molecule (SM) fluorescence microscopy allows the imaging of biomolecules in cultured cells with a precision of a few nanometres but has yet to be implemented in living adult animals. Here we used split-GFP (green fluorescent protein) fusions and complementation-activated light microscopy (CALM) for subresolution imaging of individual membrane proteins in live Caenorhabditis elegans (C. elegans). In vivo tissue-specific SM tracking of transmembrane CD4 and voltage-dependent Ca(2+) channels (VDCC) was achieved with a precision of 30 nm within neuromuscular synapses and at the surface of muscle cells in normal and dystrophin-mutant worms. Through diffusion analyses, we reveal that dystrophin is involved in modulating the confinement of VDCC within sarcolemmal membrane nanodomains in response to varying tonus of C. elegans body-wall muscles. CALM expands the applications of SM imaging techniques beyond the petri dish and opens the possibility to explore the molecular basis of homeostatic and pathological cellular processes with subresolution precision, directly in live animals.}, language = {en} } @article{WirthGlushakovaScheuermayeretal.2014, author = {Wirth, Christine C. and Glushakova, Svetlana and Scheuermayer, Matthias and Repnik, Urska and Garg, Swatl and Schaack, Dominik and Kachman, Marika M. and Weißbach, Tim and Zimmerberg, Joshua and Dandekar, Thomas and Griffiths, Gareth and Chitnis, Chetan E. and Singh, Shallja and Fischer, Rainer and Pradel, Gabriele}, title = {Perforin-like protein PPLP2 permeabilizes the red blood cell membrane during egress of Plasmodium falciparum gametocytes}, series = {Cellular Microbiology}, volume = {16}, journal = {Cellular Microbiology}, number = {5}, doi = {10.1111/cmi.12288}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120895}, pages = {709-33}, year = {2014}, abstract = {Egress of malaria parasites from the host cell requires the concerted rupture of its enveloping membranes. Hence, we investigated the role of the plasmodial perforin-like protein PPLP2 in the egress of Plasmodium falciparum from erythrocytes. PPLP2 is expressed in blood stage schizonts and mature gametocytes. The protein localizes in vesicular structures, which in activated gametocytes discharge PPLP2 in a calcium-dependent manner. PPLP2 comprises a MACPF domain and recombinant PPLP2 has haemolytic activities towards erythrocytes. PPLP2-deficient [PPLP2(-)] merozoites show normal egress dynamics during the erythrocytic replication cycle, but activated PPLP2(-) gametocytes were unable to leave erythrocytes and stayed trapped within these cells. While the parasitophorous vacuole membrane ruptured normally, the activated PPLP2(-) gametocytes were unable to permeabilize the erythrocyte membrane and to release the erythrocyte cytoplasm. In consequence, transmission of PPLP2(-) parasites to the Anopheles vector was reduced. Pore-forming equinatoxin II rescued both PPLP2(-) gametocyte exflagellation and parasite transmission. The pore sealant Tetronic 90R4, on the other hand, caused trapping of activated wild-type gametocytes within the enveloping erythrocytes, thus mimicking the PPLP2(-) loss-of-function phenotype. We propose that the haemolytic activity of PPLP2 is essential for gametocyte egress due to permeabilization of the erythrocyte membrane and depletion of the erythrocyte cytoplasm.}, language = {en} } @article{KlattHolzschuhWestphaletal.2014, author = {Klatt, Bj{\"o}rn K. and Holzschuh, Andrea and Westphal, Catrin and Clough, Yann and Smit, Inga and Pawelzik, Elke and Tscharntke, Teja}, title = {Bee pollination improves crop quality, shelf life and commercial value}, series = {Proceedings of the Royal Society B: Biological Sciences}, volume = {281}, journal = {Proceedings of the Royal Society B: Biological Sciences}, number = {1775}, doi = {10.1098/rspb.2013.2440}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120797}, year = {2014}, abstract = {Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar-acid-ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11\%. This is accounting for 0.32 billion US\$ of the 1.44 billion US\$ provided by bee pollination to the total value of 2.90 billion US\$ made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.}, language = {en} } @article{DandekarFieselmannFischeretal.2014, author = {Dandekar, Thomas and Fieselmann, Astrid and Fischer, Eva and Popp, Jasmin and Hensel, Michael and Noster, Janina}, title = {Salmonella—how a metabolic generalist adopts an intracellular lifestyle during infection}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {4}, journal = {Frontiers in Cellular and Infection Microbiology}, number = {191}, issn = {2235-2988}, doi = {10.3389/fcimb.2014.00191}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120686}, year = {2014}, abstract = {The human-pathogenic bacterium Salmonella enterica adjusts and adapts to different environments while attempting colonization. In the course of infection nutrient availabilities change drastically. New techniques, "-omics" data and subsequent integration by systems biology improve our understanding of these changes. We review changes in metabolism focusing on amino acid and carbohydrate metabolism. Furthermore, the adaptation process is associated with the activation of genes of the Salmonella pathogenicity islands (SPIs). Anti-infective strategies have to take these insights into account and include metabolic and other strategies. Salmonella infections will remain a challenge for infection biology.}, language = {en} } @article{HaydnHufnagelGrimmetal.2014, author = {Haydn, Johannes M. and Hufnagel, Anita and Grimm, Johannes and Maurus, Katja and Schartl, Manfred and Meierjohann, Svenja}, title = {The MAPK pathway as an apoptosis enhancer in melanoma}, series = {Oncotarget}, volume = {5}, journal = {Oncotarget}, number = {13}, issn = {1949-2553}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120649}, pages = {5040-53}, year = {2014}, abstract = {Inhibition of RAF/MEK/ERK signaling is beneficial for many patients with BRAFV600E-mutated melanoma. However, primary and secondary resistances restrict long-lasting therapy success. Combination therapies are therefore urgently needed. Here, we evaluate the cellular effect of combining a MEK inhibitor with a genotoxic apoptosis inducer. Strikingly, we observed that an activated MAPK pathway promotes in several melanoma cell lines the pro-apoptotic response to genotoxic stress, and MEK inhibition reduces intrinsic apoptosis. This goes along with MEK inhibitor induced increased RAS and P-AKT levels. The protective effect of the MEK inhibitor depends on PI3K signaling, which prevents the induction of pro-apoptotic PUMA that mediates apoptosis after DNA damage. We could show that the MEK inhibitor dependent feedback loop is enabled by several factors, including EGF receptor and members of the SPRED family. The simultaneous knockdown of SPRED1 and SPRED2 mimicked the effects of MEK inhibitor such as PUMA repression and protection from apoptosis. Our data demonstrate that MEK inhibition of BRAFV600E-positive melanoma cells can protect from genotoxic stress, thereby achieving the opposite of the intended anti-tumorigenic effect of the combination of MEK inhibitor with inducers of intrinsic apoptosis.}, language = {en} }