TY - JOUR A1 - Müller, T. A1 - Sebald, Walter A1 - Oschkinat, H. T1 - Antagonist design through forced electrostatic mismatch N2 - No abstract available KW - Biochemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62408 ER - TY - CHAP A1 - Fiala, Brigitte A1 - Rabenstein, R. A1 - Maschwitz, Ulrich T1 - Ant-attracting plant-structures: Food bodies of SE Asian Vitaceae N2 - No abstract available KW - Pflanzen Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-55177 ER - TY - JOUR A1 - Scheer, Ulrich A1 - Franke, Werner W. T1 - Annulate lamellae in plant cells: formation during microsporogenesis and pollen development in Canna generalis Bailey N2 - The occurrence of stacked annulate tamellae is documented for a plant cell system, namely for pollen mother cells and developing pollen grains of Canna generalis. Their structural subarchiteeture and relationship to endoplasmie reticulum (ER) and nuclear envelope cisternae is described in detail. The results demonstrate structural homology between plant and animal annulate lamellae and are compatible with, though do not prove, the view that annulate lamcllar cisternae may originate as a degenerative form of endoplasmic retieulum. Y1 - 1972 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32160 ER - TY - JOUR A1 - Linsenmair, Karl Eduard T1 - Anemomenotactic orientation in beetles and scorpions N2 - Scorpions, living in North African semideserts are - in spite of disrupting experimental interferences - able to maintain a certain direction in their natural environment in the dark on a plane surface. Under comparable laboratory conditions, excluding the possibility of light or gravity orientation, they can orient themselves if a directed air current passes over the "arena." In most cases the scorpions do not run necessarily with or against the wind, but rather maintain constant angles to the air current for anywhere from minutes to many hours. They are running anemomenotactically (ref. 1). Under identical conditions many species of beetles also orient themselves to air currents (refs. 2 to 4). The main problems to be solved in the study of anemomenotactic orientation are: (1) Which physical qualities of the air current have an influence on the anemomenotaxis? (2) With which sense organs do beetles and scorpions perceive wind directions? (3) Which physiological mechanism is the basis of anemomenotactic orientation? (4) What is the biological significance of anemomenotaxis in beetles and scorpions? With respect to these problems, more study has been done on beetles than on scorpions. Therefore, due to lack of space, I shall discuss mainly some of the results obtained in experiments with dung beetles (Geotrupes silvaticus, G. ,Stercorarius, G. armifrons, G. niger, Scarabaeus variolosus) and tenebrionid beetles (Tenebrio molitor, Pimelia grossa, P. tenuicomis, Scaurus dubius). KW - Biologie KW - Skorpion KW - Käfer Y1 - 1972 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-78118 ER - TY - JOUR A1 - Brehm, Klaus A1 - Koziol, Uriel A1 - Krohne, Georg T1 - Anatomy and development of the larval nervous system in Echinococcus multilocularis JF - Frontiers in Zoology N2 - Background The metacestode larva of Echinococcus multilocularis (Cestoda: Taeniidae) develops in the liver of intermediate hosts (typically rodents, or accidentally in humans) as a labyrinth of interconnected cysts that infiltrate the host tissue, causing the disease alveolar echinococcosis. Within the cysts, protoscoleces (the infective stage for the definitive canid host) arise by asexual multiplication. These consist of a scolex similar to that of the adult, invaginated within a small posterior body. Despite the importance of alveolar echinococcosis for human health, relatively little is known about the basic biology, anatomy and development of E. multilocularis larvae, particularly with regard to their nervous system. Results We describe the existence of a subtegumental nerve net in the metacestode cysts, which is immunoreactive for acetylated tubulin-α and contains small populations of nerve cells that are labeled by antibodies raised against several invertebrate neuropeptides. However, no evidence was found for the existence of cholinergic or serotoninergic elements in the cyst wall. Muscle fibers occur without any specific arrangement in the subtegumental layer, and accumulate during the invaginations of the cyst wall that form brood capsules, where protoscoleces develop. The nervous system of the protoscolex develops independently of that of the metacestode cyst, with an antero-posterior developmental gradient. The combination of antibodies against several nervous system markers resulted in a detailed description of the protoscolex nervous system, which is remarkably complex and already similar to that of the adult worm. Conclusions We provide evidence for the first time of the existence of a nervous system in the metacestode cyst wall, which is remarkable given the lack of motility of this larval stage, and the lack of serotoninergic and cholinergic elements. We propose that it could function as a neuroendocrine system, derived from the nervous system present in the bladder tissue of other taeniids. The detailed description of the development and anatomy of the protoscolex neuromuscular system is a necessary first step toward the understanding of the developmental mechanisms operating in these peculiar larval stages. KW - Echinococcus KW - Metacestode KW - Protoscolex KW - Nervous system KW - Neuropeptide KW - Serotonin KW - Acetylated tubulin Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96504 UR - http://www.frontiersinzoology.com/content/10/1/24 ER - TY - JOUR A1 - Zirkel, J. A1 - Cecil, A. A1 - Schäfer, F. A1 - Rahlfs, S. A1 - Ouedraogo, A. A1 - Xiao, K. A1 - Sawadogo, S. A1 - Coulibaly, B. A1 - Becker, K. A1 - Dandekar, T. T1 - Analyzing Thiol-Dependent Redox Networks in the Presence of Methylene Blue and Other Antimalarial Agents with RT-PCR-Supported in silico Modeling JF - Bioinformatics and Biology Insights N2 - BACKGROUND: In the face of growing resistance in malaria parasites to drugs, pharmacological combination therapies are important. There is accumulating evidence that methylene blue (MB) is an effective drug against malaria. Here we explore the biological effects of both MB alone and in combination therapy using modeling and experimental data. RESULTS: We built a model of the central metabolic pathways in P. falciparum. Metabolic flux modes and their changes under MB were calculated by integrating experimental data (RT-PCR data on mRNAs for redox enzymes) as constraints and results from the YANA software package for metabolic pathway calculations. Several different lines of MB attack on Plasmodium redox defense were identified by analysis of the network effects. Next, chloroquine resistance based on pfmdr/and pfcrt transporters, as well as pyrimethamine/sulfadoxine resistance (by mutations in DHF/DHPS), were modeled in silico. Further modeling shows that MB has a favorable synergism on antimalarial network effects with these commonly used antimalarial drugs. CONCLUSIONS: Theoretical and experimental results support that methylene blue should, because of its resistance-breaking potential, be further tested as a key component in drug combination therapy efforts in holoendemic areas. KW - methylene blue KW - malaria KW - elementary mode analysis KW - drug KW - resistance KW - combination therapy KW - pathway KW - metabolic flux Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123751 N1 - This is an open access article. Unrestricted non-commercial use is permitted provided the original work is properly cited. VL - 6 ER - TY - JOUR A1 - Liu, Ruiqi A1 - Kinoshita, Masato A1 - Adolfi, Mateus C. A1 - Schartl, Manfred T1 - Analysis of the role of the Mc4r system in development, growth, and puberty of medaka JF - Frontiers in Endocrinology N2 - In mammals the melanocortin 4 receptor (Mc4r) signaling system has been mainly associated with the regulation of appetite and energy homeostasis. In fish of the genus Xiphophorus (platyfish and swordtails) puberty onset is genetically determined by a single locus, which encodes the mc4r. Wild populations of Xiphophorus are polymorphic for early and late-maturing individuals. Copy number variation of different mc4r alleles is responsible for the difference in puberty onset. To answer whether this is a special adaptation of the Mc4r signaling system in the lineage of Xiphophorus or a more widely conserved mechanism in teleosts, we studied the role of Mc4r in reproductive biology of medaka (Oryzias latipes), a close relative to Xiphophorus and a well-established model to study gonadal development. To understand the potential role of Mc4r in medaka, we characterized the major features of the Mc4r signaling system (mc4r, mrap2, pomc, agrp1). In medaka, all these genes are expressed before hatching. In adults, they are mainly expressed in the brain. The transcript of the receptor accessory protein mrap2 co-localizes with mc4r in the hypothalamus in adult brains indicating a conserved function of modulating Mc4r signaling. Comparing growth and puberty between wild-type and mc4r knockout medaka revealed that absence of Mc4r does not change puberty timing but significantly delays hatching. Embryonic development of knockout animals is retarded compared to wild-types. In conclusion, the Mc4r system in medaka is involved in regulation of growth rather than puberty. KW - medaka KW - Mc4r KW - knockout KW - puberty KW - growth Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201472 VL - 10 ER - TY - THES A1 - Dinev, Dragomir T1 - Analysis of the role of extracellular signal regulated kinase (ERK5) in the differentiation of muscle cells T1 - Analyse der Rolle der extrazellulären signalregulierten Kinase (ERK5) in der Differenzierung von Muskelzellen N2 - The MEK5/ ERK5 kinase module is a relatively new discovered mitogen-activated protein kinase (MAPK) signalling pathway with a poorly defined physiological function. Since ERK5 and its upstream activator MEK5 are abundant in skeletal muscle a function of the cascade during muscle differentiation was examined. ERK5 becomes activated upon induction of differentiation in mouse myoblasts. The selective activation of the pathway results in promoter activation of differentiation-specific genes, such as the cdk-inhibitor p21 gene, the myosin light chain (MLC1A) gene, or an E-box containing promoter element, where myogenic basic-helix-loop-helix proteins such as MyoD or myogenin bind. Moreover, myogenic differentiation is completely blocked, when ERK5 expression is inhibited by antisense RNA. The effect can be detected also on the expression level of myogenic determination and differentiation markers such as p21, MyoD and myogenin. Another new finding is that stable expression of ERK5 in C2C12 leads to differentiation like phenotype and to increased p21 expression levels under growth conditions. These results provide first evidence that the MEK5/ERK5 MAP kinase cascade is critical for early steps of muscle cell differentiation. N2 - MEK5/ ERK5 ist ein erst kürzlich entdeckter MAPK- Signalweg, dessen physiologische Funktion noch wenig verstanden ist. Da ERK5 und der in der Kaskade oberhalb liegende Aktivator MEK5 in Skelettmuskeln hoch expremiert werden, wurde eine Funktion der Kaskade während des Muskel-Differenzierung untersucht. ERK5 wird nach einer Induktion der Differenzierung in Maus-Myoblasten aktiviert. Die gezielte Aktivierung dieses Signalwegs führt zur Induzierung von Promotoren differenzierungs-spezifischer Gene, wie z.B. des cdk-Inhibitors p21, der MLC1A, oder eines Promotors, der E-Boxen enthält, woran myogene Basische-Helix- loop- Helix Proteine, wie MyoD oder Myogenin binden können. Darüber hinaus ist die Muskeldifferenzierung völlig blockiert, wenn die Expression von ERK5 mittels antisense-RNA inhibiert wird. Diesen Effekt kann man auch an hand der Menge von exprimierten muskelspezifischen Differenzierungsproteinen, wie p21, MyoD und Myogenin nachweisen. Eine weitere neue Entdeckung ist, daß stabile Expression von ERK5 in C2C12 Zellen zu einem differenzierungsähnlichen Phänotyp und gesteigerter p21 Expression unter Wachstum-bedingungen führt. Diese Ergebnisse geben erste Anhaltspunkte, daß der MEK5/ ERK5 MAP Kinase Signalweg entscheidend für frühe Stadien der Muskeldifferenzierung ist. KW - Muskelzelle KW - Zelldifferenzierung KW - Signaltransduktion KW - Proteinkinasen KW - ERK5 KW - MEK5 KW - MEF2C KW - MyoD KW - Muskeldifferenzierung KW - Kinase KW - ERK5 KW - MEK5 KW - MEF2C KW - MyoD KW - muscle differentiation KW - kinase Y1 - 2001 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-1180481 ER - TY - THES A1 - Fernández-Mora, Eugenia T1 - Analysis of the maturation of Rhodococcus equi-containing vacuoles in macrophages T1 - Analyse der Reifung von Rhodococcus equi-enthaltenden Phagosomen in Makrophagen N2 - Rhodococcus equi is a Gram-positive intracellular pathogen which can cause severe bronchopneumonia in foals. In recent years, the role of this bacterium as human pathogen has been noted, as R.equi infections in humans have increase in frequency. This increase is associated with the rise in immunosupressed individuals, specially AIDS patients, where infection leads to symptoms and pathology similar to those seen in foals with a high mortality rate. Due to its capability to survive and multiply in murine and equine macrophages, R.equi has been classified as a facultative intracellular bacterium. R.equi is found frequently in macrophages in alveolar infiltrate from infected animals. The pathogenicity of R.equi depends on its ability to exist and multiply inside macrophages and has been associated with the presence of virulence plasmids. It has been observed that, inside foal alveolar macrophages, R.equi-containing vacuoles (RCVs) do not mature into phagolysosomes. However, most of the intracellular events during R.equi infection have not been investigated in detail. The aim of this study was to elucidate the intracellular compartmentation of R.equi and the mechanism by which the bacteria avoid destruction in host macrophages. The importance of the virulence-associated plasmids of R.equi for the establishment of RCVs was also evaluated. Furthermore, the intracellular fate of viable and non-viable R.equi was compared in order to study whether viability of R.equi influeciantes the establishment of RCVs. In this study, the RCV was characterized by using a variety of endocytic markers to follow the path of the bacteria trhough murine macropages. Transmission electron microscopy-base analysis showed that R.equi was found equally frequently in phagosomes with loosely or thightly apposed membranes, and RCV often contains numerous membranous vesicles. Laser scanning microscopy of infected macrophages showed that the majority of phagosomes containing R.equi acquired transiently the early endosomal markers Rab5, Ptlns3P, and EEA-1, suggesting initially undisturbed phagosome maturation. Although the RCV acquired some late endosomal markers, such as Rab7, LAMP-1, and Lamp-2, they did not acquired vATPase, did not interact with pre-labeled lysosomes, and failed to acidify. These data clearly suggest that the RCV is a compartment which has left vacuoles that resemble multivesicular body compartments (MVB), which are transport intermediates between early and late endosomes and display internal vesicles very similar to the ones observed within RCVs. Analyisis of several R.equi strains containing either VapA- or VapB-expressing plasmids or neither demonstrated that the possession of the virulence-associated plasmids does not affect phagosome trafficking over a two hour period of infection. The finding that non-viable R.equi was still able to inhibit phagosome maturation (although not to the same extent as viable R.equi did) suggests that heat-insensitive factors, such as cell periphery lipids, may play a major role in inhibition of phagosome maturation, although heat-sensitive factors may also be involved. N2 - Rhodococcus equi ist ein Gram-positives, fakultativ intrazelulläres Bakterium, das unter anderem die Ursache von Bronchopneumonien bei Fohlen ist. Menschen und andere Säugetiere können ebenfalls von Infektionen mit R. equi betroffen sein. In den letzten Jahren ist die Häufigkeit klinischer Infektionen mit R. equi bei Menschen gestiegen. Die wachsende Anzahl an mmunosupprimierten Patienten (hauptsächlich AIDS-Patienten) liegt dieser Zunahme an Infektionen zugrunde. Die Symptomatologie und Pathologie der Infektion mit R. equi ist bei AIDS-Patienten und Fohlen ähnlich. Die Sterblichkeitsrate ist in beiden Fällen hoch. Die Fähigkeit der Rhodokokken, innerhalb von Makrophagen zu überleben und sich zu vermehren, ist mit dem Vorhandensein von Virulenzplasmiden (virulence-associated plasmids) verbunden. Innerhalb des Makrophagen befinden sich die Rhodokokken in einem Phagosom, das nicht mit Lysosomen fusioniert. Die genaue Kompartimentierung der Rhodococcus equi-enthaltenden Phagosomen in Makrophagen war bisher unbekannt und wurde deshalb in der vorliegenden Promotionsarbeit untersucht. Mit Hilfe mehrerer endozytischer Marker wurde das R. equi-enthaltende Kompartiment charakterisiert. Mögliche Unterschiede zwischen der Kompartimentierung von R. equi(+)- und R. equi(-)-enthaltenden Phagosomen ist ebenfalls Thema dieser Promotionsarbeit. Weiterhin wurde die Etablierung des phagosomalen Kompartiments für jeweils lebende und tote Rhodokokken verglichen. Transmissionselektronenmikroskopische Analysen haben gezeigt, dass die Phagosomenmembran Rhodococcus equi-enthaltender Phagosomen sowohl locker als auch eng anliegend sein kann (50%). Darüber hinaus wurden häufig zahlreiche, membranöse Vesikel in R. equi-enthaltenden Phagosomen gefunden. Diese Phagosomen zeigen somit Ähnlichkeiten zu Multivesicular Bodies. Multivesicular Bodies sind intermediäre Kompartimente zwischen frühen und späten Endosomen und zeigen ebenfalls eine Vielzahl von internen Vesikeln. Untersuchungen am konfokalen Lasermikroskop ergaben, dass die Mehrheit der R. equi-enthaltenden Phagosomen die früh endosomalen Marker Rab5, PtIns3P und EEA-1 transient akquirieren. Dieser Befund deutet auf eine ungestörte phagosomale Reifung im frühen Stadium hin. Trotz der beobachteten Akquisition der spät endosomalen Marker Rab7, LAMP-1 und LAMP-2 konnte keine Akquisition der vATPase, keine Interaktion mit vormarkierten Lysosomen und keine Ansäuerung von R.equi-enthaltenden Phagosomen nachgewiesen werden. Diese Ergebnisse weisen darauf hin, dass R. equi-enthaltende Phagosomen das früh endosomale Stadium abschließen, aber einen typisch spät endosomale Zustand nicht erreichen. Die Analyse unterschiedlicher R. equi-Stämme, die entweder vapA- oder vapB-exprimierende Virulenzplasmide enthalten, hat gezeigt, dass die Anwesenheit von Virulenzplasmiden die phagosomale Reifung über eine Infektionsperiode von zwei Stunden nicht beeinflusst. Getötete Rhodokokken waren in der Lage, die phagosomale Reifung zu inhibieren, aber in geringerem Ausmaß als lebende Rhodokokken. Das weist darauf hin, dass hitze-insensitive Faktoren (wie zum Beispiel Lipide der Zellwand) zur Inhibierung der phagosomalen Reifung entscheidend sind, obwohl dazu auch hitze-sensitive Faktoren (wie Proteine) relevant sein können. KW - Rhodococcus equi KW - Makrophage KW - Vakuole KW - Endosome KW - Phagosome KW - Rhodococcus KW - Mycobacterium KW - Reifung KW - endosome KW - phagosome KW - Rhodococcus KW - Mycobacterium KW - maturation Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-14049 ER - TY - JOUR A1 - Groh, Claudia A1 - Rössler, Wolfgang T1 - Analysis of Synaptic Microcircuits in the Mushroom Bodies of the Honeybee JF - Insects N2 - Mushroom bodies (MBs) are multisensory integration centers in the insect brain involved in learning and memory formation. In the honeybee, the main sensory input region (calyx) of MBs is comparatively large and receives input from mainly olfactory and visual senses, but also from gustatory/tactile modalities. Behavioral plasticity following differential brood care, changes in sensory exposure or the formation of associative long-term memory (LTM) was shown to be associated with structural plasticity in synaptic microcircuits (microglomeruli) within olfactory and visual compartments of the MB calyx. In the same line, physiological studies have demonstrated that MB-calyx microcircuits change response properties after associative learning. The aim of this review is to provide an update and synthesis of recent research on the plasticity of microcircuits in the MB calyx of the honeybee, specifically looking at the synaptic connectivity between sensory projection neurons (PNs) and MB intrinsic neurons (Kenyon cells). We focus on the honeybee as a favorable experimental insect for studying neuronal mechanisms underlying complex social behavior, but also compare it with other insect species for certain aspects. This review concludes by highlighting open questions and promising routes for future research aimed at understanding the causal relationships between neuronal and behavioral plasticity in this charismatic social insect. KW - mushroom body KW - microglomeruli KW - projection neurons KW - Kenyon cells KW - dendritic specializations KW - structural synaptic plasticity KW - behavioral plasticity KW - vision KW - olfaction Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200774 SN - 2075-4450 VL - 11 IS - 1 ER - TY - JOUR A1 - Alsheimer, Manfred A1 - Link, Jana A1 - Leubner, Monika A1 - Schmitt, Johannes A1 - Göb, Eva A1 - Benavente, Ricardo A1 - Jeang, Kuan-Teh A1 - Xu, Rener T1 - Analysis of Meiosis in SUN1 Deficient Mice Reveals a Distinct Role of SUN2 in Mammalian Meiotic LINC Complex Formation and Function N2 - LINC complexes are evolutionarily conserved nuclear envelope bridges, composed of SUN (Sad-1/UNC-84) and KASH (Klarsicht/ANC-1/Syne/homology) domain proteins. They are crucial for nuclear positioning and nuclear shape determination, and also mediate nuclear envelope (NE) attachment of meiotic telomeres, essential for driving homolog synapsis and recombination. In mice, SUN1 and SUN2 are the only SUN domain proteins expressed during meiosis, sharing their localization with meiosis-specific KASH5. Recent studies have shown that loss of SUN1 severely interferes with meiotic processes. Absence of SUN1 provokes defective telomere attachment and causes infertility. Here, we report that meiotic telomere attachment is not entirely lost in mice deficient for SUN1, but numerous telomeres are still attached to the NE through SUN2/KASH5-LINC complexes. In Sun12/2 meiocytes attached telomeres retained the capacity to form bouquetlike clusters. Furthermore, we could detect significant numbers of late meiotic recombination events in Sun12/2 mice. Together, this indicates that even in the absence of SUN1 telomere attachment and their movement within the nuclear envelope per se can be functional. Author summary: Correct genome haploidization during meiosis requires tightly regulated chromosome movements that follow a highly conserved choreography during prophase I. Errors in these movements cause subsequent meiotic defects, which typically lead to infertility. At the beginning of meiotic prophase, chromosome ends are tethered to the nuclear envelope (NE). This attachment of telomeres appears to be mediated by well-conserved membrane spanning protein complexes within the NE (LINC complexes). In mouse meiosis, the two main LINC components SUN1 and SUN2 were independently described to localize at the sites of telomere attachment. While SUN1 has been demonstrated to be critical for meiotic telomere attachment, the precise role of SUN2 in this context, however, has been discussed controversially in the field. Our current study was targeted to determine the factual capacity of SUN2 in telomere attachment and chromosome movements in SUN1 deficient mice. Remarkably, although telomere attachment is impaired in the absence of SUN1, we could find a yet undescribed SUN1-independent telomere attachment, which presumably is mediated by SUN2 and KASH5. This SUN2 mediated telomere attachment is stable throughout prophase I and functional in moving telomeres within the NE. Thus, our results clearly indicate that SUN1 and SUN2, at least partially, fulfill redundant meiotic functions. KW - telomeres KW - spermatocytes KW - Oocytes KW - meiosis KW - protein domains KW - cytoskeleton KW - synapsis KW - homologous chromosomes Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-111355 ER - TY - JOUR A1 - Winkler, Christoph A1 - Hong, Yunhan A1 - Wittbrodt, Joachim A1 - Schartl, Manfred T1 - Analysis of heterologous and homologous promoters and enhancers in vitro and in vivo by gene transfer into Japanese medaka (Oryzias latipes) and Xiphophorus N2 - Efficient expression systems are required for analysis of gene regulation and function in teleost fish. To develop such systems, a nurober of inducible or constitutive promoter and enhancer sequences of fish or higher vertebrate origin were tested for activity in a variety of fish celllines andin embryos of the Japanese medaka fish (Oryzias latipes) and Xiphophorus. The activity of the different promoterenhancer combinations were quantitated. Considerable differences were found for some constructs if tested in vitro or in vivo. From the data obtained, a set of expression vectors for basic research as weH as for aquaculture purposes were established. KW - Schwertkärpfling KW - Japankärpfling KW - Gentransfer KW - Enhancer KW - Promotor KW - In vitro KW - In vivo Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86796 ER - TY - JOUR A1 - Maierhofer, Anna A1 - Flunkert, Julia A1 - Dittrich, Marcus A1 - Müller, Tobias A1 - Schindler, Detlev A1 - Nanda, Indrajit A1 - Haaf, Thomas T1 - Analysis of global DNA methylation changes in primary human fibroblasts in the early phase following X-ray irradiation JF - PLoS ONE N2 - Epigenetic alterations may contribute to the generation of cancer cells in a multi-step process of tumorigenesis following irradiation of normal body cells. Primary human fibroblasts with intact cell cycle checkpoints were used as a model to test whether X-ray irradiation with 2 and 4 Gray induces direct epigenetic effects (within the first cell cycle) in the exposed cells. ELISA-based fluorometric assays were consistent with slightly reduced global DNA methylation and hydroxymethylation, however the observed between-group differences were usually not significant. Similarly, bisulfite pyrosequencing of interspersed LINE-1 repeats and centromeric α-satellite DNA did not detect significant methylation differences between irradiated and non-irradiated cultures. Methylation of interspersed ALU repeats appeared to be slightly increased (one percentage point; p = 0.01) at 6 h after irradiation with 4 Gy. Single-cell analysis showed comparable variations in repeat methylation among individual cells in both irradiated and control cultures. Radiation-induced changes in global repeat methylation, if any, were much smaller than methylation variation between different fibroblast strains. Interestingly, α-satellite DNA methylation positively correlated with gestational age. Finally, 450K methylation arrays mainly targeting genes and CpG islands were used for global DNA methylation analysis. There were no detectable methylation differences in genic (promoter, 5' UTR, first exon, gene body, 3' UTR) and intergenic regions between irradiated and control fibroblast cultures. Although we cannot exclude minor effects, i.e. on individual CpG sites, collectively our data suggest that global DNA methylation remains rather stable in irradiated normal body cells in the early phase of DNA damage response. KW - DNA methylation KW - fibroblasts KW - methylation KW - alu elements KW - DNA damage KW - epigenetics KW - cancer treatment Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170895 VL - 12 IS - 5 ER - TY - JOUR A1 - Förnzler, Dorothee A1 - Wittbrodt, Joachim A1 - Schartl, M.anfred T1 - Analysis of an esterase linked to a locus involved in the regulation of the melanoma oncogene and isolation of polymorphic marker sequences in Xiphophorus N2 - Melanoma formation in Xiphophorus hybrids is mediated by a growth factor receptor tyrosine kinase oncogene encoded by the Tu locus. In the wild-type parental fish no tumors occur due to the activity of a locus that regulates the activity of the melanoma oncogene. Molecu/ar identification of this regulatory locus (R) requires a precise physical map of the chromosomal region. Therefore we studied esterase isozymes in Xiphophorus, two of which have been previously reported to be linked to locus R. We confinn that ES 1 is a distant marker for R ( approx. 30cM), and contrary to earlier studies, we show that this isozyme is present in all species of the genus and at similar activity Ievels in all organs tested. ES4, which has also been reported to be linked to R, was found to be a misclassification of liver ES1. In an attempt to identify markersthat bridge the large distance between ESl and R, we have generated DNA probes which are highly polymorphic. They will be useful in finding Iandmarks on a physical map of the R-containing chromosomal region. KW - Physiologische Chemie KW - Xiphophorus KW - melanoma ; oncogene regulation ; esterase ; molecular marker sequences Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61726 ER - TY - THES A1 - Schuster, Sarah T1 - Analysis of \(Trypanosoma\) \(brucei\) motility and the infection process in the tsetse fly vector T1 - Analyse der Motilität von \(Trypanosoma\) \(brucei\) und dem Infektionsprozess in der Tsetsefliege N2 - African trypanosomes are protist pathogens that are infective for a wide spectrum of mammalian hosts. Motility has been shown to be essential for their survival and represents an important virulence factor. Trypanosoma brucei is transmitted by the bite of the bloodsucking tsetse fly, the only vector for these parasites. The voyage through the fly is complex and requires several migration, proliferation and differentiation steps, which take place in a defined order and in specific fly tissues. The first part of this doctoral thesis deals with the establishment of the trypanosome tsetse system as a new model for microswimmer analysis. There is an increasing interdisciplinary interest in microbial motility, but a lack of accessible model systems. Therefore, this work introduces the first enclosed in vivo host parasite system that is suitable for analysis of diverse microswimmer types in specific microenvironments. Several methods were used and adapted to gain unprecedented insights into trypanosome motion, the fly´s interior architecture and the physical interaction between host and parasite. This work provides a detailed overview on trypanosome motile behavior as a function of development in diverse host surroundings. In additional, the potential use of artificial environments is shown. This can be used to partly abstract the complex fly architecture and analyze trypanosome motion in defined nature inspired geometries. In the second part of the thesis, the infection of the tsetse fly is under investigation. Two different trypanosome forms exist in the blood: proliferative slender cells and cell cycle arrested stumpy cells. Previous literature states that stumpy cells are pre adapted to survive inside the fly, whereas slender cells die shortly after ingestion. However, infection experiments in our laboratory showed that slender cells were also potentially infective. During this work, infections were set up so as to minimize the possibility of stumpy cells being ingested, corroborating the observation that slender cells are able to infect flies. Using live cell microscopy and fluorescent reporter cell lines, a comparative analysis of the early development following infection with either slender or stumpy cells was performed. The experiments showed, for the first time, the survival of slender trypanosomes and their direct differentiation to the procyclic midgut stage, contradicting the current view in the field of research. Therefore, we can shift perspectives in trypanosome biology by proposing a revised life cycle model of T. brucei, where both bloodstream stages are infective for the vector. N2 - Afrikanische Trypanosomen sind pathogene Protisten, die ein breites Spektrum von Säugetierwirten infizieren. Es wurde gezeigt, dass die Zellmotilität für das Überleben der Parasiten essenziell ist und einen wichtigen Virulenzfaktor darstellt. Trypanosoma brucei wird durch den Biss der blutsaugenden Tsetsefliege übertragen, dem einzigen Vektor für diese Parasiten. Der Entwicklungszyklus in der Fliege ist komplex und beinhaltet mehrere Migrations-, Proliferations- und Differenzierungsschritte, die in einer definierten Reihenfolge und in spezifischen Fliegenorganen stattfinden. Der erste Teil dieser Doktorarbeit beschäftigt sich mit der Etablierung des Trypanosomen Tsetse Systems als ein neues Modell für Motilitätsanalysen. Es besteht ein wachsendes interdisziplinäres Interesse an mikrobieller Motilität, aber es fehlen zugängliche Mikroschwimmersysteme. Deswegen stellt diese Arbeit das erste abgeschlossene in vivo Wirt Parasit System vor, das für Analysen von verschiedenen Mikroschwimmertypen in spezifischen Umgebungen geeignet ist. Verschiedene Methoden wurden benutzt und adaptiert, um sowohl Einblicke in die Trypanosomenbewegung, die innere Fliegenarchitektur als auch die physikalischen Wechselwirkungen zwischen Wirt und Parasit zu erhalten. Diese Arbeit bietet einen detaillierten Überblick über das motile Verhalten von Trypanosomen als Funktion der Entwicklung in diversen Wirtsumgebungen. Zusätzlich ist die potenzielle Nutzung von artifiziellen Umgebungen gezeigt. Diese können benutzt werden, um die komplexe Architektur der Fliege teilweise zu abstrahieren und die Trypanosomenbewegung in definierten und von der Nature inspirierten Geometrien zu analysieren. Im zweiten Teil dieser Arbeit wurde die Infektion der Fliege genauer betrachtet. Im Blut existieren zwei verschiedene Trypanosomenformen: proliferierende ‘slender’ und Zellzyklus arretierte ‘stumpy’ Zellen. Bisherige Literatur besagt, dass stumpy Zellen präadaptiert sind, um in der Fliege zu überleben, wohingegen slender Zellen kurz nach der Aufnahme sterben. Dennoch konnten Infektionsexperimente in unserem Labor zeigen, dass auch slender Zellen potenziell infektiös sind. Während dieser Arbeit wurden weitere Infektionen so durchgeführt, dass die Möglichkeit für die Aufnahme von stumpy Zellen minimiert wurde und die Infektionskapazität der slender Zellen bestätigt werden konnte. Durch Lebendzell Mikroskopie mit fluoreszenten Reporterzelllinien wurde eine vergleichende Analyse für die frühe Entwicklung von slender und stumpy Parasiten nach der Infektion durchgeführt. Die Experimente zeigten zum ersten Mal das Überleben von slender Trypanosomen in der Tsetsefliege und ihre direkte Differenzierung in das prozyklische Mitteldarmstadium. Sie widersprechen demnach der aktuellen Auffassung im Forschungsbereich. Demzufolge können wir von einem Perspektivwechsel in der Trypanosomenbiologie sprechen und schlagen einen revidierten Lebenszyklus für T. brucei vor, in dem beide Blutstromformen für den Vektor infektiös sind. KW - Motilität KW - Trypanosomen KW - Tsetsefliege KW - Parasit KW - tsetse fly KW - motility KW - trypanosome KW - vector-parasite interaction KW - microswimming Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-192691 ER - TY - THES A1 - Wawrowsky, Kolja Alexander T1 - Analysis and Visualization in Multidimensional Microscopy T1 - Analyse und Visualisierung in der multidimensionalen Mikroskopie N2 - The live sciences currently undergo a paradigm shift to computer aided discoveries. Discoveries in the live sciences were historically made by either direct observation or as a result of chemical assays. Today we see a growing shift toward computer aided analysis and visualization. This gradual process happens in microscopy. Multidimensional laser scanning microscopy can acquire very complex multichannel data from fixed or live specimen. New probes such as visible fluorescent proteins let us observe the expression of genes and track protein localization. Ion sensitive dyes change intensity with the concentration of ions in the cell. The laser scanning confocal allows us to record these processes in three dimensions over time. This work demonstrates the application of software analysis to multidimensional microscopy data. We introduce methods for volume investigation, ion flux analysis and molecular modeling. The visualization methods are based on a multidimensional data model to accommodate complex datasets. The software uses vector processing and multiple processors to accelerate volume rendering and achieve interactive rendering. The algorithms are based on human visual perception and allow the observer a wide range of mixed render modes. The software was used to reconstruct the pituitary development in zebrafish and observe the degeneration of neurons after injury in a mouse model. Calicum indicator dyes have long been used to study calcium fluxes. We optimized the imaging method to minimize impact on the cell. Live cells were imaged continuously for 45 minutes and subjected to increasing does of a drug. We correlated the amplitude of calcium oscillations to increasing doses of a drug and obtain single cell dose response curves. Because this method is very sensitive and measures single cell responses it has potential in drug discovery and characterization. Microtubules form a dynamic cytoskeleton, which is responsible for cell shape, intracellular transport and has an integral role in mitosis. A hallmark of microtubule organization is lateral interactions. Microtubules are bundles by proteins into dense structures. To estimate the contribution of this bundling process, we created a fractal model of microtubule organization. This model demonstrates that morphology of complex microtubule arrays can be explained by bundling alone. In summary we showed that advances in software for visualization, data analysis and modeling lead to new discoveries. N2 - Die biologische Forschung befindet sich in einem Paradigmenwandel, in dem Endeckungen immer mehr von Computeranalyse ermöglicht werden. Entdeckungen in der biologischen Forschung wurden historisch gesehen durch direkte Beobachtung and mit Hilfe chemischer Analysemethoden gemacht. Heute sehen wir einen wachsenden Trend zur computerunterstützten Analyse und Visualisierung. Dieser graduelle Umschwung spielt sich auch in der Mikroskopie ab. Multidimensionale Laser Scanning Mikroskopie kann sehr komplexe Multikanalbilder von fixierten oder lebenden Präparaten aufnehmen. Neue Methoden (wie z.B. fluoreszierende Proteine) erlauben es, Genexpression und Proteinlokalisierung direkt sichtbar zu machen. Ionensensitive Farbstoffe ändern ihre Helligkeit mit der Konzentration der Ionen in der Zelle. Die konfokale Mikroskopie erlaubt es, diese Änderungen dreidimensional über die Zeit aufzunehmen. Die hier vorgestellte Arbeit demonstriert die Anwendung speziell entwickelter Software für die Analyse multidimensionaler Daten. Die hierbei entwickelten Methoden wurden für Volumendarstellung, Ionenfluxanalyse und zur molekularen Modellierung eingesetzt. Die Visualisierungsmethoden basieren auf einem multidimensionalen Datenmodel, um auch komplexe Daten verarbeiten zu können. Die Software benutzt Vektorverarbeitung und Multiprozessorunterstützung um Volumendarstellung schneller und interaktiv zu machen. Die Algorithmen beruhen auf Erkenntnissen der Wahrnehmungsforschung und erlauben es dem Anwender, eine Reihe von verschiedenen Darstellungsmodi zu kombinieren. Die Software wurde erstmals verwendet, um einerseits die Entwicklung der Hypophyse im Zebrafisch zu rekonstruieren, und andererseits die Degenerierung von Neuronen im Mausmodell bildlich zu verfolgen. Kalziumfarbstoffe wurden schon länger zum Studium von Kalziumoszillationen in Zellen eingesetzt. Wir optimierten die Bildaufnahmemethode um Schädigungen der Zelle zu minimieren. Zellen wurden kontinuierlich in 45 Minuten Zeitintervallen aufgenommen und dabei wachsenden Dosen der zu untersuchenden Substanz ausgesetzt. Durch Korrelation von Dosis und Oszillationsamplitude konnten pharmakologische Wirkungskurven für jede einzelne Zelle ermittelt werden. Diese Methode hat wegen der hohen Sensitivität und Auflösung bis zur einzelnen Zelle Potential für pharmakologische Untersuchungen. Mikrotubuli formen ein dynamisches Zytoskelett, das für Zellform und intrazellularen Transport zuständig ist und eine integrale Rolle bei der Mitose spielt. Eine besondere Eigenschaft der Mikrotubuli ist die laterale Interaktion. Mikrotubuli werden von Motorproteinen zu dichten Strukturen gebündelt. Um den möglichen Einfluß dieses Vorgangs auf die Organisation der Mikotubuli zu testen, wurde ein fraktales Model erstellt. Dieses Modell demonstriert, daß die komplexe Organisation der Mikrotubuli in einigen Fällen allein mit dem Bündelungsprozess erklärt werden kann. Zusammenfassend konnte in dieser Arbeit demonstriert werden, daß der Einsatz speziell entwickelter Software für Visualisierung, Datenanalyse und Modellierung zu neuen wissenschaftlichen Erkenntnissen führen kann. KW - Konfokale Mikroskopie KW - Laser-Rastermikroskopie KW - Leica-Mikroskopie und -Systeme GmbH KW - Mikroskopie KW - Visualisierung KW - Bildverarbeitung KW - Mikrotubuli KW - Visualization KW - Image Processing KW - Microtubules Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-23867 ER - TY - INPR A1 - Dandekar, Thomas T1 - Analysing the phase space of the standard model and its basic four forces from a qubit phase transition perspective: implications for large-scale structure generation and early cosmological events N2 - The phase space for the standard model of the basic four forces for n quanta includes all possible ensemble combinations of their quantum states m, a total of n**m states. Neighbor states reach according to transition possibilities (S-matrix) with emergent time from entropic ensemble gradients. We replace the “big bang” by a condensation event (interacting qubits become decoherent) and inflation by a crystallization event – the crystal unit cell guarantees same symmetries everywhere. Interacting qubits solidify and form a rapidly growing domain where the n**m states become separated ensemble states, rising long-range forces stop ultimately further growth. After that very early events, standard cosmology with the hot fireball model takes over. Our theory agrees well with lack of inflation traces in cosmic background measurements, large-scale structure of voids and filaments, supercluster formation, galaxy formation, dominance of matter and life-friendliness. We prove qubit interactions to be 1,2,4 or 8 dimensional (agrees with E8 symmetry of our universe). Repulsive forces at ultrashort distances result from quantization, long-range forces limit crystal growth. Crystals come and go in the qubit ocean. This selects for the ability to lay seeds for new crystals, for self-organization and life-friendliness. We give energy estimates for free qubits vs bound qubits, misplacements in the qubit crystal and entropy increase during qubit decoherence / crystal formation. Scalar fields for color interaction and gravity derive from the permeating qubit-interaction field. Hence, vacuum energy gets low only inside the qubit crystal. Condensed mathematics may advantageously model free / bound qubits in phase space. KW - phase space KW - cosmology KW - emergent time KW - qubit KW - phase transition KW - bit Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-298580 ER - TY - JOUR A1 - Chipperfield, Joseph D. A1 - Dytham, Calvin A1 - Hovestadt, Thomas T1 - An Updated Algorithm for the Generation of Neutral Landscapes by Spectral Synthesis N2 - Background: Patterns that arise from an ecological process can be driven as much from the landscape over which the process is run as it is by some intrinsic properties of the process itself. The disentanglement of these effects is aided if it possible to run models of the process over artificial landscapes with controllable spatial properties. A number of different methods for the generation of so-called ‘neutral landscapes’ have been developed to provide just such a tool. Of these methods, a particular class that simulate fractional Brownian motion have shown particular promise. The existing methods of simulating fractional Brownian motion suffer from a number of problems however: they are often not easily generalisable to an arbitrary number of dimensions and produce outputs that can exhibit some undesirable artefacts. Methodology: We describe here an updated algorithm for the generation of neutral landscapes by fractional Brownian motion that do not display such undesirable properties. Using Monte Carlo simulation we assess the anisotropic properties of landscapes generated using the new algorithm described in this paper and compare it against a popular benchmark algorithm. Conclusion/Significance: The results show that the existing algorithm creates landscapes with values strongly correlated in the diagonal direction and that the new algorithm presented here corrects this artefact. A number of extensions of the algorithm described here are also highlighted: we describe how the algorithm can be employed to generate landscapes that display different properties in different dimensions and how they can be combined with an environmental gradient to produce landscapes that combine environmental variation at the local and macro scales. KW - Landschaft KW - Monte-Carlo-Simulation KW - Brownsche Bewegung Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68938 ER - TY - CHAP A1 - Riehl, Rüdiger A1 - Schartl, Manfred A1 - Anders, Fritz T1 - An ultrastructural study of melanoma in Xiphophorus N2 - Melanotic melanoma (MM) of Xiphophorus (Teleostei: Poeciliidae) was studied by conventional preparations and freeze-etch preparations for electron microscopy. MM of Xiphophorus exhibits tightly packed pigment cells with prominent dendritic processes and interdigitations of their plasma membranes. The most impressive feature of MM cells is the occurrence of Iarge lobulated nuclei with numerous nuclear pores and some nuclear pockets. Abundant spheroidal or ellipsoidal melanosomes (diameter 200-650 nm) and vesicular structures are distributed throughout the cellular dendrites, whereas the perinucJear cytoplasm is free of melanosomes. A further characteristic feature of melanoma cells in fish is the occurrence of melanosome complexes (i.e., "compound melanosomes"). These melanosome complexes consist of a few to numerous melanosomes, which are enveloped by a separate rnembrane. Pinocytotic vesicles couJd be demonstrated with distinct differences in frequency and distribution patterns, indicating differences in the metabolic activities of the cells in the same melanoma. Intercellular junctions are lacking in the MM cells. The conventional TEM technique showed clear advantages in the demonstration of intemal architecture of organelles, whereas FE bad considerable potential in respect to the visualization of membrane surface specializations. KW - Schwertkärpfling KW - Krebs KW - Ultrastruktur Y1 - 1985 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-70978 ER - TY - JOUR A1 - Higgins, M. J. A1 - Smilinich, N. J. A1 - Sait, S. A1 - Koenig, A. A1 - Pongratz, J. A1 - Gessler, Manfred A1 - Richard III., C. W. A1 - James, M. R. A1 - Sanford, J. P. A1 - Kim, B.-W. A1 - Cattelane, J. A1 - Nowak, N. J. A1 - Winterpacht, A. A1 - Zabel, B. U. A1 - Munroe, D. J. A1 - Bric, E. A1 - Housman, D. E. A1 - Jones, C. A1 - Nakamura, Y. A1 - Gerhard, D. S. A1 - Shows, T. B. T1 - An Ordered NotI Fragment Map of Human Chromosome Band 11p15 N2 - An ordered NotI fragment map containing over 60 loci and encompassing approximately 17 Mb has been constructed for human chromosome band llpl5. Forty-two probes, including 11 NotI-linking cosmids, were subregionaUy mapped to llpl5 using a subset of the Jl-deletion hybrids. These and 23 other probes defining loci previously mapped to 11p15 were hybridized to genomic DNA digested with NotI and 5 other infrequently cleaving restriction enzymes and separated by pulsed-field gel electrophoresis. Thirty-nine distinct NotI fragments were detected encompassing approximately 85% of the estimated length of llp15. The predicted order of the gene loci used is cenMYODI- PTH-CALCA-ST5-RBTNI-HPX-HBB-RRMlTH/ INS!1GF2-H19-CTSD-MUC2-DRD4-HRAS-RNHtel. This map wiu allow higher resolution mapping of new Ilp15 markers, facilitate positional cloning of disease genes, and provide a framework for the physical mapping of llp15 in clone contigs. KW - Genom / Genkartierung / Genanalyse Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-45766 ER -