@article{PoethkeHovestadtMitesser2003,
  author    = {Poethke, Hans-Joachim and Hovestadt, Thomas and Mitesser, Oliver},
  title     = {Local extinction and the evolution of dispersal rates: Causes and correlations},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47718},
  year      = {2003},
  abstract  = {We present the results of individual-based simulation experiments on the evolution of dispersal rates of organisms living in metapopulations. We find conflicting results regarding the relationship between local extinction rate and evolutionarily stable (ES) dispersal rate depending on which principal mechanism causes extinction: if extinction is caused by environmental catastrophes eradicating local populations, we observe a positive correlation between extinction and ES dispersal rate; if extinction is a consequence of stochastic local dynamics and environmental fluctuations, the correlation becomes ambiguous; and in cases where extinction is caused by dispersal mortality, a negative correlation between local extinction rate and ES dispersal rate emerges. We conclude that extinction rate, which both affects and is affected by dispersal rates, is not an ideal predictor for optimal dispersal rates.},
  subject      = {Ausbreitung},
  language  = {en}
}
@phdthesis{Kackstaetter2003,
  author    = {Kackstaetter, Uwe R.},
  title     = {Contaminant diffusion and sorption of an artificial leachate in selected geologic barriers of Frankonia, Bavaria, Germany},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-16151},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The geologic barrier represents the final contact between a landfill and the environment. Ideally suited are clays and mudstones because of sufficient vertical and lateral extent, low hydraulic conductivities and high sorptive characteristics. Since hydraulic conductivity is no longer the single criteria to determine transport and retardation of contaminants in geologic landfill barrier materials, diffusive and sorptive characteristics of 4 different clay and mudstone lithologies in Northern Bavaria, were investigated. Cored samples from various depths were included in this study and subjected to evaluations of geochemistry, mineralogy, physical parameters, sorption and diffusion. A transient double reservoir with decreasing source concentration was designed and constructed using clear polycarbonate cylinders for undisturbed clay plugs of 2 to 4cm thickness. Samples were also fitted with internal electrical conductivity probes to determine the migration of the diffusive front. A multi chemical species synthetic landfill leachate was contrived to simulate and evaluate natural pollutant conditions. A computational method for determining mineralogy from geochemical data was also developed. It was found that sorptive processes are mostly controlled by the quality and type of fine grained phyllosilicates and the individual chemical species involved exhibited linear, Freundlich, as well as Langmuir sorption properties. Effective diffusion and sorption coefficients were also determined using POLLUTEv6 (GAEA, 1997) software and receptor reservoir concentrations for K, Na, Ca, Cu, NH4, Cl, NO3, SO4, and concentration totals at predetermined time intervals. Anion exclusion proved to be a major factor in the diffusion process and was used to explain many observed anomalies. Furthermore, diffusion coefficients were found not to be static with a multi chemical species leachate, but actually varied during the course of the experiment. Strong indications point toward the major role of pore space quality, shape, and form as control of diffusive properties of a geologic barrier. A correlation of CECNa of the samples with De may point to a possible deduction of diffusive properties for multi species leachates without extensive and time consuming laboratory tests},
  language  = {en}
}
@phdthesis{Brandt2003,
  author    = {Brandt, S{\"o}nke},
  title     = {Metamorphic evolution of ultrahigh-temperature granulite facies and upper amphibolite facies rocks of the Epupa Complex, NW Namibia},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10930},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The high-grade metamorphic Epupa Complex (EC) of north-western Namibia constitutes the south-western margin of the Archean to Proterozoic Congo Craton. The north-eastern portion of the EC has been geochemically and petrologically investigated in order to reconstruct its tectono-metamorphic evolution. Two distinct metamorphic units have been recognized, which are separated by ductile shear zones: (1) Upper amphibolite facies rocks (Orue Unit) and (2) ultrahigh-temperature (UHT) granulite facies rocks (Epembe Unit). The rocks of the EC are transsected by a large anorthosite massif, the Kunene Intrusive Complex (KIC). The Orue Unit and the Epembe Unit were affected by two distinct Mesoproterozoic metamorphic events, as is evident from differences in their metamorphic grade, in the P-T paths and in the age of peak-metamorphism: (1) The Orue Unit consists of a Palaeoproterozoic volcano-sedimentary sequence, which was intruded by large masses of I-type granitoids and by rare mafic dykes. During the Mesoproterozoic (1390-1318 Ma) the Orue Unit rocks underwent upper amphibolite facies metamorphism. The volcano-sedimentary sequence is constituted by interlayered basaltic amphibolites and rhyolitic felsic gneisses, with intercalations of migmatitic metagreywackes, migmatitic metapelites, metaarkoses and calc-silicate rocks. The Orue Unit was subdivided into three parts, which record similar heating-cooling paths but represent individual crustal levels: Heating led to the partial replacement of amphibole, biotite and muscovite through dehydration melting reactions. The peak-metamorphic P-T conditions of c. 700°C, 6.5 +/- 1.0 kbar (south-eastern part), c. 820°C, 8 +/- 0.5 kbar (south-western part) and c. 800°C, 6.0 +/- 1.0 kbar (northern part) correlate well with the mineral assemblage in the metapelites, i.e. Grt-Bt-Sil gneisses and schist in the south-eastern and south-western region and (Grt-)Crd-Bt gneisses in the northern part. Peak-metamorphism was followed by retrograde cooling to middle amphibolite facies conditions. Contact metamorphism, related with the intrusion of the anorthosites, is restricted to the direct contact to the KIC and recorded by massive metapelitic Grt-Sil-Crd felses, formed under upper amphibolite facies conditions (c. 750°C, c. 6.5 kbar). (2) The Epembe Unit consists of a Palaeoproterozoic volcano-sedimentary succession, which was intruded by small bodies of S-type granitoids and by andesitic dykes. All these rocks underwent UHT granulite facies metamorphism during the early Mesoproterozoic (1520-1447 Ma). The volcano-sedimentary succession is dominated by interlayered basaltic two-pyroxene granulites and rhyolitic felsic granulites. Migmatitic metapelites and metagreywackes are intercalated in the metavolcanites. Sapphirine-bearing MgAl-rich gneisses occur as restitic schlieren in the migmatitic metagreywackes. Reconstructed anti-clockwise P-T paths are subdivided into several distinct stages: During prograde near-isobaric heating to UHT conditions at c. 7 kbar biotite- or hornblende-bearing mineral assemblages were almost completely replaced by anhydrous mineral assemblages through various dehydration melting reactions. A subsequent pressure increase of 2-3 kbar led to the formation of the peak-metamorphic mineral assemblages Grt-Opx and (Grt-)Opx-Cpx in the orthogneisses and Grt-Opx, Grt-Sil and (Grt-)(Spr-)Opx-Sil-Qtz in the paragneisses. UHT-Metamorphism is proved by conventional geothermobarometry (970 +/- 70°C; 9.5 +/- 2.5 kbar), by the very high Al content of peak-metamorphic orthopyroxene (up to 11.9 wt.\% Al2O3) in many paragneisses and by Opx-Sil-Qtz assemblages in the MgAl-rich gneisses. Post-peak decompression is recorded by several corona and symplectite textures, formed at the expense of the peak-metamorphic phases: Initial UHT decompression of about ca. 2 kbar to 940 +/- 60°C at 8 +/- 2 kbar is mainly evident from the formation of sapphirine-bearing symplectites in the Opx-Sil gneisses. Subsequent high-temperature decompression to 6 +/- 2 kbar at 800 +/- 60°C resulted in the formation of Crd-Opx-Spl, Crd-Opx and Spl-Crd symplectites. Subsequent near-isobaric cooling to upper amphibolite conditions of 660 +/- 30°C at 5 +/- 1.5 kbar led to the re-growth of biotite, hornblende, sillimanite and garnet. During continued decompression orthopyroxene and cordierite were formed at the expense of biotite in several paragneisses. In a geodynamic model UHT metamorphism of the Epembe Unit is correlated with the formation of a large magma chamber at the mantle-crust boundary, which forms the source for the anorthosites of the KIC. In contrast, amphibolite facies metamorphism of the Orue Unit is ascribed to a regional contact metamorphic event, caused by the emplacement of the anorthositic crystal mushes in the middle crust.},
  subject      = {Namibia <Nordwest>},
  language  = {en}
}
@phdthesis{Schoell2003,
  author    = {Sch{\"o}ll, Achim},
  title     = {High-resolution investigation of the electronic structure of organic thin films},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10809},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Die vorliegende Arbeit befasst sich mit der elektronischen Struktur organischer D{\"u}nnfilme. Eine zentrale Frage dabei ist der Einfluss der Wechselwirkung zwischen den Molek{\"u}len in der kondensierten Phase und der Wechselwirkung an metall-organischen Grenzfl{\"a}chen auf die elektronischen Eigenschaften. Dazu wurden die experimentellen Methoden Photoelektronenspektroskopie (PES) und R{\"o}ntgenabsorptionsspektroskopie (NEXAFS) mit h{\"o}chster Energieaufl{\"o}sung angewandt. Zus{\"a}tzlich wurden ab initio Rechnungen zur theoretischen Simulation von NEXAFS Spektren durchgef{\"u}hrt. Haupts{\"a}chlich wurden d{\"u}nne, vakuumsublimierte Filme aromatischer Modellmolek{\"u}le mit sauerstoffhaltigen funktionellen Gruppen (NTCDA, PTCDA, NDCA, BPDCA und ANQ) auf Ag(111) Oberfl{\"a}chen untersucht. Die ausgew{\"a}hlten Molek{\"u}le besitzen wegen ihrer großen delokalisierten p-Elektronensysteme sehr interessante Eigenschaften f{\"u}r die Anwendung in elektronischen Bauelementen. Dank der hohen Energieaufl{\"o}sung von Synchrotronstrahlungsquellen der dritten Generation war es erstmals m{\"o}glich, die Schwingungsfeinstruktur in den NEXAFS Spektren dieser kondensierten großen Molek{\"u}le sichtbar zu machen. Der Vergleich der Daten verschiedener Molek{\"u}le liefert dabei interessante Einblicke in den Kopplungmechanismus zwischen dem elektronischen {\"U}bergang und der Schwingungsanregung. Obwohl die Molek{\"u}le eine Vielzahl verschiedener Schwingungsmoden besitzen, kann man in deren NEXAFS Spektren beobachten, dass die elektronischen {\"U}berg{\"a}nge jeweils an haupts{\"a}chlich eine Schwingungsmode koppeln. Die hochaufgel{\"o}sten XPS Spektren der Molek{\"u}le NTCDA, PTCDA, NDCA, BPDCA und ANQ zeigen bestimmte systematische Unterschiede, so dass diese Spektren als Fingerabdruck f{\"u}r die jeweilige Substanz verwendet werden k{\"o}nnen. Durch die vergleichende Auswertung der Spektren konnten die 1s Bindungsenergien aller chemisch unterschiedlichen Kohlenstoff- und Sauerstoffatome bestimmt werden. Zus{\"a}tzliche Strukturen in den Spektren k{\"o}nnen shake-up Satelliten zugeschrieben werden. Die f{\"u}nf Molek{\"u}le stellen ein ideales Modellsystem dar, um fundamentale Aspekte der Rumpfelektronenspektroskopie zu untersuchen, wie Anfangs- und Endzustandseffekte und Satelliten, die durch die intramolekulare und intermolekulare Elektronendichteverteilung im Grund- und rumpfionisierten Zustand beeinflusst werden. Ein wichtiger Punkt dieser Dissertation sind spektroskopische Untersuchungen strukturell unterschiedlicher NTCDA Monolagenphasen auf Ag(111), deren Existenz aus vorangegangenen Arbeiten bekannt ist. Deutliche Unterschiede in der elektronischen Struktur der verschiedenen Phasen, die auf die Metall-Adsorbat Wechselwirkung zur{\"u}ckzuf{\"u}hren sind, konnten sowohl mittels XPS als auch mittels NEXAFS aufgezeigt werden. Sowohl f{\"u}r die komprimierte also auch f{\"u}r die relaxierte NTCDA Monolage kann die Bindung ans Substrat als schwach chemisorptiv charakterisiert werden, was eindeutig aus der Analyse der Satellitenstrukturen in den O 1s und C 1s XPS Spektren hervorgeht, die durch die dynamische Abschirmung durch Ladungstransfer vom Substrat erzeugt werden. Die NEXAFS Daten zeigen konsistent eine teilweise Besetzung des NTCDA LUMOs. Sowohl f{\"u}r die komprimierte als auch f{\"u}r die relaxierte NTCDA Monolage finden hochinteressante Phasen{\"u}berg{\"a}nge in ungeordnete Tieftemperaturphasen beim Abk{\"u}hlen auf 160 K statt. Dabei wird die Adsorbat-Substrat Wechselwirkung st{\"a}rker und das LUMO wird vollst{\"a}ndig besetzt. Dies kann in den NEXAFS Spektren anhand des Verschwindens der zugh{\"o}rigen {\"U}berg{\"a}nge beobachtet werden. Die XPS Spektren zeigen gleichzeitig eine deutliche Abnahme der Intensit{\"a}t schlecht abgeschirmter Photoemissionszust{\"a}nde, was auf die nun effektivere Ladungstransferabschirmung zur{\"u}ckzuf{\"u}hren ist. F{\"u}r den Phasen{\"u}bergang der relaxierten Monolage konnte mittels temperaturabh{\"a}ngiger NEXAFS Messungen eindeutig ein Hystereseverhalten gezeigt und die Hysteresekurve bestimmt werden. Die Hysterese betr{\"a}gt etwa 20 K. Des weiteren wurde aus SPA-LEED Messungen die Aktivierungsenergie f{\"u}r den Phasen{\"u}bergang der relaxierten Monolage beim Abk{\"u}hlen auf ca. 60 meV bestimmt. Schließlich wurden NEXAFS Untersuchungen an Poly{\"a}thylenproben mit verschiedenem Komonomergehalt durchgef{\"u}hrt. Unterschiede in den Absorptionsspektren von Proben mit unterschiedlichem Komonomeranteil konnten eindeutig auf die unterschiedliche Kristallinit{\"a}t der Proben zur{\"u}ckgef{\"u}hrt werden, indem eine hochkristalline Probe in situ bis zur Schmelztemperatur geheizt wurde. Ab initio Rechnungen an einer Modelmatrix aus Butanmolek{\"u}len zeigen, dass die Spektren von kristallinem und amorphem Poly{\"a}thylen aufgrund der intermolekularen Wechselwirkung deutliche Unterschiede haupts{\"a}chlich f{\"u}r Resonanzen mit starkem Rydberg Charakter aufweisen. Damit lassen sich die Unterschiede in den Poly{\"a}thylenspektren durch die {\"U}berlagerung der Signaturen der kristallinen und amorphen Anteile erkl{\"a}ren, die je nach Kristallinit{\"a}t der Probe in unterschiedlichen Verh{\"a}ltnissen vorliegen.},
  subject      = {D{\"u}nne Schicht},
  language  = {en}
}
@phdthesis{Dem2003,
  author    = {Dem, Claudiu Dorin},
  title     = {Design and construction of a device for light scattering studies on airborne particles},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9605},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {This thesis is concerned with the development of an on-line in-situ device for a chemical characterisation of flowing aerosols. The thesis describes the principles and most important features of such a system, allowing also on-line measurements using Raman spectroscopy as a diagnostic technique An analysis of the effect of forced oscillations on the motion of the particle dispersed in a gas flow is given in Chapter 2. Also the most important particle parameters are introduced. A review of the particle/fluid interaction in laminar air flows and the response of the particle is presented. In Chapter 3 the behaviour of the particle under different external conditions (ion bombardment and electric fields) is extended. A brief review of the most important particle charging theories (diffusion, field, and alternating potential charging) shows, that the effect of the electrical properties (represented by the dielectric constant) of the particles affects the charging process. A non-contact method for particle charge measurement was also presented. In the second part of the chapter, the interaction between the electric field and the charged particle for the purpose of particle trapping is illustrated. The most common systems like the two or four ring electrodynamic balance and the quadrupole trap are pointed out. In Chapter 4 a short review of the possibility of using scattered light to study aerosol particles is presented. First, the conditions and the facilities of using the Mie theory for particle size and refractive index determination are mentioned, then some features concerning the classical treatment of the Raman effect are presented Supported by the theoretical considerations exposed in Chapter 2, 3, and 4 the construction and the tests of different devices are presented in Chapter 5. Following the goal of the thesis, first an overview of the used materials and methods for particle generation is presented. Then, the constructed charging devices are described (from the mechanical and electrical point of view) and compared by measuring the acquired charge on the particle. Charged particles can be trapped in different containers. Two types of axially symmetric electrodynamic balances (two ring or an extended four ring configuration) were presented. For a deeper understanding these systems were studied using analytic and numerical methods. Considering the presented purpose of the work another type of trapping system has been developed, namely the quadrupole trap. A similar theoretical characterisation (in term's of Mathieu equation) as for the electrodynamic balance was presented pointing out some specific features of this system. The incoming particle stream will be focused to the centre of the system simultaneously also the applied DC and AC potential onto the tube electrodes, yields a stable trapping of one or more particles. Chapter 6 consists of two parts: the system for single particle and for many particles investigation. The individual devices presented in Chapter 5 are now put together. The first part presents the method and the experimental realisation of a set-up for solid particle injection. In order to suppress the phase injection disadvantage found for the electrodynamic balance a developed program processes the information obtained from a particle cloud through an adequate electronic detection system, and reduces the number of particles until just one single particle is trapped. The method for one particle investigation can be extended for many particles. Using the presented set-up the particles are moved from one quadrupole to another and transformed from a particle cloud to a particle stream. A linearity between an external vertical mounted detector and the formed image of the particle stream on the CCD camera has been observed and used for simultaneous detection of many particles by Raman spectroscopy. For both methods Raman results are presented. One limitation of Raman Spectroscopy is the relatively long integration time needed for adequate signal-to-noise ratio. There are two factors which influence the integration time: first the incident radiation and the detector sensitivity, and second the intensity of the Raman bands. Using a CCD detector, the desired detector sensitivity should be achieved. So, the improvement of the signal-to-noise ratio should be the next goal in the system development. In order to reduce the integration time an optical system including optic fibres and the integration of an FT-Raman module operating in the visible region is planed. The goal of this work was to develop and construct an instrument for on-line in-situ single particle investigation by Raman spectroscopy. With the presented experimental set-up and the developed program the purpose of the work, the on-line in-situ near atmospheric pressure aerosol investigation was achieved. The Raman spectroscopy has been used successfully for a chemical characterisation of the aerosol particles.},
  subject      = {Aerosol},
  language  = {en}
}
@phdthesis{Tyrsin2003,
  author    = {Tyrsin, Oleg},
  title     = {Role of Raf family members in mouse development},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9453},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Raf Proteine sind Serin/Threonin Kinasen, die als zentrale Elemente des Ras, Raf, Mek, Map Kinase Wegs, an der Weiterleitung von extrazellul{\"a}ren Signalen von der Zellmembran zu nukle{\"a}ren Effektoren beteiligt sind. Auf diese Weise kontrollieren sie elementare Prozesse wie Proliferation, Differenzierung und das {\"U}berleben von Zellen. In S{\"a}ugetieren wurden drei funktionelle Gene (A-, B- and C-raf) beschrieben. Aus biochemischen Untersuchungen ergibt sich, dass die Isozyme {\"u}berlappende aber auch differentielle Funktionen {\"u}bernehmen. Allerdings wurde ein differenziertes Verst{\"a}ndnis der jeweiligen spezifischen Rolle dadurch erschwert, dass in den meisten Zelltypen verschiedene Raf-Isozyme expremiert werden und dass wegen der Vielzahl der Aktivatoren und Effektoren eine eindeutige Isoform-Zuordnung schwer m{\"o}glich war. Aufgrund der Beteiligung an verschiedenen Krankheitsbildern, insbesondere der Tumorentstehung und -progression, ist jedoch die Aufkl{\"a}rung der Isozym-spezifischen Funktionen von vorranginger wissenschaftlicher Bedeutung. B-Raf hat unter den Raf Kinasen die h{\"o}chste Kinaseaktivit{\"a}t und zeigt antiapoptotische Eigenschaften. B-Raf knockout M{\"a}use zeigen eine allgemeine Wachstumsverz{\"o}gerung und sterben zwischen E10,5 und E12,5 aufgrund fehlentwickelter Gef{\"a}sse in Folge massiver Apoptose differenzierter Endothelzellen. [1]. Um die Lethalit{\"a}t des B-Raf-/- (KO) Ph{\"a}notyps zu {\"u}berkommen und um die Redundanz der B-Raf Proteine weiter zu untersuchen, wurden M{\"a}use generiert, die unter der Kontrolle des B-Raf Promoters statt B-Raf eine A-Raf cDNA exprimieren. Nur in einem Fall entwickelte sich eine ausgewachsene p20 Maus ohne sichtbare Entwicklungsdefekte oder Verhaltensauff{\"a}lligkeiten. Dar{\"u}ber hinaus wurden lebende Embryonen mit normaler Entwicklung aber reduzierter Gr{\"o}sse mit niedriger Inzidenz zwischen E12,5d und E16,5d beobachtet. In allen diesen F{\"a}llen fanden wir ein intaktes Gef{\"a}ßsystem. Andererseits waren Neurogenese und die Bewegung der neuralen Vorl{\"a}uferzellen in den {\"u}berlebenden Embryonen gest{\"o}rt, was in einigen F{\"a}llen zu unterentwickelten Hirnregionen f{\"u}hrte. Mittels TUNEL bzw. PCNA Assay konnten wir zeigen, dass mehr apoptotische und weniger proliferierende Zellen in ventrikul{\"a}rer und subventrikul{\"a}rer Zone der Hirn Ventrikel und im Striatum der KIN Embryonen zu finden sind. Außerdem wurden in einer Reihe von Geweben von E13,5d und in den Lungen von E16,5d Embryonen, vermehrt apoptotische Zellen beobachtet. Dies war in der einen ausgewachsenen KIN Maus nicht der Fall. Diese zeigte einen reduzierten Anteil an neuronalen Vorl{\"a}uferzellen in der subgranul{\"a}ren Zone des Hippocampus und an reifen Neuronen im Riechkolben. Ansonsten waren aber keine St{\"o}rungen der Neurogenese in der ausgewachsenen KIN Maus detektierbar. Fibroblasten die aus KIN Embryonen etabliert wurden, zeigten im Vergleich zu Wildtypzellen reduzierte F{\"a}higkeit zur Proliferation und erh{\"o}hte Sensibilit{\"a}t gegen{\"u}ber Apoptoseausl{\"o}sern. Die erh{\"o}hte Apoptosetendenz spiegelte sich auf molekularer Ebene in einer Reduktion an antiapoptotischen Molek{\"u}len wieder. Aktive ERK und Akt Kinase sind erniedrigt. Außerdem war von dem bekannten Raf Substrat BAD, weniger an der inaktiven phosphorylierten Form zu beobachten, wodurch bei gleicher Menge Gesamtprotein auf ein Mehr an proapoptotischem unphosphoryliertem BAD geschlossen werden kann. Zusammengefasst zeigen diese Daten, dass die Substitution von B-Raf durch die weniger aktive A-Raf Kinase zwar die endotheliale Apoptose verhindern kann, die die Ursache f{\"u}r das fr{\"u}he Absterben der B-Raf-/- (KO) M{\"a}use ist, dass aber die normale Entwicklung dennoch entscheidend gest{\"o}rt ist.},
  subject      = {Maus},
  language  = {en}
}
@phdthesis{Kraus2003,
  author    = {Kraus, Daniela},
  title     = {Conformal pseudo-metrics and some applications},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9193},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The point of departure for the present work has been the following free boundary value problem for analytic functions \$f\$ which are defined on a domain \$G \subset \mathbb{C}\$ and map into the unit disk \$\mathbb{D}= \{z \in \mathbb{C} : |z|<1 \}\$. Problem 1: Let \$z_1, \ldots, z_n\$ be finitely many points in a bounded simply connected domain \$G \subset \mathbb{C}\$. Show that there exists a holomorphic function \$f:G \to \mathbb{D}\$ with critical points \$z_j\$ (counted with multiplicities) and no others such that \$\lim_{z \to \xi} \frac{|f'(z)|}{1-|f(z)|^2}=1\$ for all \$\xi \in \partial G\$. If \$G=\mathbb{D}\$, Problem 1 was solved by K?nau [5] in the case of one critical point, and for more than one critical point by Fournier and Ruscheweyh [3]. The method employed by K?nau, Fournier and Ruscheweyh easily extends to more general domains \$G\$, say bounded by a Dini-smooth Jordan curve, but does not work for arbitrary bounded simply connected domains. In this paper we present a new approach to Problem 1, which shows that this boundary value problem is not an isolated question in complex analysis, but is intimately connected to a number of basic open problems in conformal geometry and non-linear PDE. One of our results is a solution to Problem 1 for arbitrary simply connected domains. However, we shall see that our approach has also some other ramifications, for instance to a well-known problem due to Rellich and Wittich in PDE. Roughly speaking, this paper is broken down into two parts. In a first step we construct a conformal metric in a bounded regular domain \$G\subset \mathbb{C}\$ with prescribed non-positive Gaussian curvature \$k(z)\$ and prescribed singularities by solving the first boundary value problem for the Gaussian curvature equation \$\Delta u =-k(z) e^{2u}\$ in \$G\$ with prescribed singularities and continuous boundary data. This is related to the Berger-Nirenberg problem in Riemannian geometry, the question which functions on a surface R can arise as the Gaussian curvature of a Riemannian metric on R. The special case, where \$k(z)=-4\$ and the domain \$G\$ is bounded by finitely many analytic Jordan curves was treated by Heins [4]. In a second step we show every conformal pseudo-metric on a simply connected domain \$G\subseteq \mathbb{C}\$ with constant negative Gaussian curvature and isolated zeros of integer order is the pullback of the hyperbolic metric on \$\mathbb{D}\$ under an analytic map \$f:G \to \mathbb{D}\$. This extends a theorem of Liouville which deals with the case that the pseudo-metric has no zeros at all. These two steps together allow a complete solution of Problem 1. Contents: Chapter I contains the statement of the main results and connects them with some old and new problems in complex analysis, conformal geometry and PDE: the Uniformization Theorem for Riemann surfaces, the problem of Schwarz-Picard, the Berger-Nirenberg problem, Wittich's problem, etc.. Chapter II and III have preparatory character. In Chapter II we recall some basic results about ordinary differential equations in the complex plane. In our presentation we follow Laine [6], but we have reorganized the material and present a self-contained account of the basic features of Riccati, Schwarzian and second order differential equations. In Chapter III we discuss the first boundary value problem for the Poisson equation. We shall need to consider this problem in the most general situation, which does not seem to be covered in a satisfactory way in the existing literature, see [1,2]. In Chapter IV we turn to a discussion of conformal pseudo-metrics in planar domains. We focus on conformal metrics with prescribed singularities and prescribed non-positive Gaussian curvature. We shall establish the existence of such metrics, that is, we solve the corresponding Gaussian curvature equation by making use of the results of Chapter III. In Chapter V we show that every constantly curved pseudo-metric can be represented as the pullback of either the hyperbolic, the euclidean or the spherical metric under an analytic map. This is proved by using the results of Chapter II. Finally we give in Chapter VI some applications of our results. [1,2] Courant, H., Hilbert, D., Methoden der Mathematischen Physik, Erster/ Zweiter Band, Springer-Verlag, Berlin, 1931/1937. [3] Fournier, R., Ruscheweyh, St., Free boundary value problems for analytic functions in the closed unit disk, Proc. Amer. Math. Soc. (1999), 127 no. 11, 3287-3294. [4] Heins, M., On a class of conformal metrics, Nagoya Math. J. (1962), 21, 1-60. [5] K?nau, R., L?gentreue Randverzerrung bei analytischer Abbildung in hyperbolischer und sph?ischer Geometrie, Mitt. Math. Sem. Giessen (1997), 229, 45-53. [6] Laine, I., Nevanlinna Theory and Complex Differential Equations, de Gruyter, Berlin - New York, 1993.},
  subject      = {Freies Randwertproblem},
  language  = {en}
}
@phdthesis{Wollmershaeuser2003,
  author    = {Wollmersh{\"a}user, Timo},
  title     = {A theory of managed floating},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8676},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {After the experience with the currency crises of the 1990s, a broad consensus has emerged among economists that such shocks can only be avoided if countries that decided to maintain unrestricted capital mobility adopt either independently floating exchange rates or very hard pegs (currency boards, dollarisation). As a consequence of this view which has been enshrined in the so-called impossible trinity all intermediate currency regimes are regarded as inherently unstable. As far as the economic theory is concerned, this view has the attractive feature that it not only fits with the logic of traditional open economy macro models, but also that for both corner solutions (independently floating exchange rates with a domestically oriented interest rate policy; hard pegs with a completely exchange rate oriented monetary policy) solid theoretical frameworks have been developed. Above all the IMF statistics seem to confirm that intermediate regimes are indeed less and less fashionable by both industrial countries and emerging market economies. However, in the last few years an anomaly has been detected which seriously challenges this paradigm on exchange rate regimes. In their influential cross-country study, Calvo and Reinhart (2000) have shown that many of those countries which had declared themselves as 'independent floaters' in the IMF statistics were charaterised by a pronounced 'fear of floating' and were actually heavily reacting to exchange rate movements, either in the form of an interest rate response, or by intervening in foreign exchange markets. The present analysis can be understood as an approach to develop a theoretical framework for this managed floating behaviour that - even though it is widely used in practice - has not attracted very much attention in monetary economics. In particular we would like to fill the gap that has recently been criticised by one of the few 'middle-ground' economists, John Williamson, who argued that "managed floating is not a regime with well-defined rules" (Williamson, 2000, p. 47). Our approach is based on a standard open economy macro model typically employed for the analysis of monetary policy strategies. The consequences of independently floating and market determined exchange rates are evaluated in terms of a social welfare function, or, to be more precise, in terms of an intertemporal loss function containing a central bank's final targets output and inflation. We explicitly model the source of the observable fear of floating by questioning the basic assumption underlying most open economy macro models that the foreign exchange market is an efficient asset market with rational agents. We will show that both policy reactions to the fear of floating (an interest rate response to exchange rate movements which we call indirect managed floating, and sterilised interventions in the foreign exchange markets which we call direct managed floating) can be rationalised if we allow for deviations from the assumption of perfectly functioning foreign exchange markets and if we assume a central bank that takes these deviations into account and behaves so as to reach its final targets. In such a scenario with a high degree of uncertainty about the true model determining the exchange rate, the rationale for indirect managed floating is the monetary policy maker's quest for a robust interest rate policy rule that performs comparatively well across a range of alternative exchange rate models. We will show, however, that the strategy of indirect managed floating still bears the risk that the central bank's final targets might be negatively affected by the unpredictability of the true exchange rate behaviour. This is where the second policy measure comes into play. The use of sterilised foreign exchange market interventions to counter movements of market determined exchange rates can be rationalised by a central bank's effort to lower the risk of missing its final targets if it only has a single instrument at its disposal. We provide a theoretical model-based foundation of a strategy of direct managed floating in which the central bank targets, in addition to a short-term interest rate, the nominal exchange rate. In particular, we develop a rule for the instrument of intervening in the foreign exchange market that is based on the failure of foreign exchange market to guarantee a reliable relationship between the exchange rate and other fundamental variables.},
  language  = {en}
}
@phdthesis{Huelsewig2003,
  author    = {H{\"u}lsewig, Oliver},
  title     = {Bank lending and monetary policy transmission in Germany},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8686},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {This study investigates the credit channel in the transmission of monetary policy in Germany by means of a structural analysis of aggregate bank loan data. We base our analysis on a stylized model of the banking firm, which specifies the loan supply decisions of banks in the light of expectations about the future course of monetary policy. Using the model as a guide, we apply a vector error correction model (VECM), in which we identify long-run cointegration relationships that can be interpreted as loan supply and loan demand equations. In this way, the identification problem inherent in reduced form approaches based on aggregate data is explicitly addressed. The short-run dynamics is explored by means of innovation analysis, which displays the reaction of the variables in the system to a monetary policy shock. The main implication of our results is that the credit channel in Germany appears to be effective, as we find that loan supply effects in addition to loan demand effects contribute to the propagation of monetary policy measures.},
  language  = {en}
}
@phdthesis{Kleen2003,
  author    = {Kleen, Thomas Oliver},
  title     = {Dissociated expression of granzyme B and IFN-gamma by T lymphocytes in HIV-1 infected individuals and its implications for Tc1 effector diversity},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8460},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {A CD8+ cell-mediated host defense relies on cognate killing of infected target cells and on local inflammation induced by the secretion of IFN-g. Using assays of single cell resolution, it was studied to what extent these two effector function of CD8+ cells are linked. Granzyme B (GzB) is stored in cytolytic granules of CD8+ cells and its secretion is induced by antigen recognition of these cells. Following entry into the cytosol GzB induces apoptosis in the target cells. It was measured whether GzB release by individual CD8+ cells is accompanied by the secretion of IFN-gƒnƒnand of other cytokines. HIV peptide libraries were tested on bulk peripheral blood mononuclear cells and on purified CD4+ and CD8+ cells obtained from HIV infected individuals. The library included a panel of previously defined HLA class I restricted HIV peptides and an overlapping 20-mer peptide-series that covered the entire gp120 molecule. To characterize the in vivo differentiation state of the T-cells, freshly isolated lymphocytes were tested in assays of 24h duration. The data showed that only ~20\% of the peptides triggered the release of both GzB and IFN-g from CD8+ cells. The majority of the HIV peptides induced either GzB or IFN-g, ~40\% in each category. The GzB positive, IFN-g negative CD8+ cells did not produce IL-4 or IL-5, which suggests that they do not correspond to Tc2 cells but represent a novel Tc1 subclass, which was termed Tc1c. Also the IFN-g positive, GzB negative CD8+ cell subpopulation represents a yet undefined CD8+ effector cell lineage that was termed Tc1b. Tc1b and Tc1c cells are likely to make different, possibly antagonistic contributions to the control of HIV infection. Since IFN-g activates HIV replication in latently infected macrophages, the secretion of this cytokine by Tc1b cells in the absence of killing may have adverse effects on the host defense. In contrast, cytolysis by Tc1c cells in the absence of IFN-g production might represent the protective class of response. Further studies in the field of Tc1 effector cell diversity should lead to valuable insights for management of infections and developing rationales for vaccine design.},
  subject      = {Antigen CD8},
  language  = {en}
}
@phdthesis{RamirezPineda2003,
  author    = {Ramirez Pineda, Jos{\´e} Robinson},
  title     = {Dendritic cells activated by CpG motifs are potent inducers of a Th1 immune response that protects mice against leishmaniasis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8410},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The present investigation report a protocol to obtain dendritic cells (DC) that protects mice against fatal leishmaniasis. DC were generated from bone marrow precursors, pulsed with leishmanial antigen and activated with CpG oligodeoxinucleotides. Mice that were vaccinated with these cells were strongly protected against the clinical and parasitological manifestations of leishmaniasis and developed a Th1 immune response. protection was solid and long-lasting, and was also dependent of the via of administration. Whe the mechanism of protection was studied, it was observed that the availability of the cytokine interleukin-12 at the time of vaccination was a key requirement, but that the source of this cytokine is not the donor cells but unidentified cells from the recipients.},
  subject      = {Leishmaniose},
  language  = {en}
}
@phdthesis{Hupp2003,
  author    = {Hupp, Thomas},
  title     = {Ab Initio Treatment of Complex Systems Kohn-Sham Orbitals for Multi Reference Methods and the Base Pairing Properties of Xanthine},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8244},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Die vorliegende Arbeit besteht aus zwei Teilen. Der erste untersucht die Eignung von LHF-Orbitalen f{\"u}r Multireferenzverfahren. Das Ziel dieses Teils ist eine effizientere Berechnung angeregter Zust{\"a}nde, was zur spektroskopischen Charakterisierung vieler organischer und bioorganischer Molek{\"u}le wichtig ist. Der zweite Teil befasst sich mit bioorganischen Fragestellungen und untersucht die Paarungseigenschaften der Purinbase Xanthin. Es wird unter anderem die unerwartet hohe Stabilit{\"a}t der Xanthin Selbstpaarung in Alanyl-PNA erkl{\"a}rt und es wird untersucht, auf welche Weise Xanthin in der DNA mutagene Fehlpaarungen mit Thymin eingehen kann. Teil1: Im Unterschied zu HF- und Standard-DFT-Methoden f{\"u}hrt der LHF-Ansatz zu einem vollst{\"a}ndig gebundenen Orbitalspektrum, da Coulomb-Selbstwechselwirkungen im LHF-Ansatz exakt korrigiert werden. Durch die Korrektur der Coulomb-Selbstwechselwirkungen sind im LHF-Ansatz auch die Energien der besetzten Orbitale nicht wie in Standard-DFT-Methoden zu h{\"o}heren Werten verschoben, so dass das Koopmans' Theorem g{\"u}ltig bleibt und die besetzten LHF-Orbitale etwas kompakter als Standard-DFT-Orbitale sind. Die vorliegende Arbeit zeigt, dass beide Eigenschaften deutliche Vorteile f{\"u}r MR-Verfahren darstellen. Die virtuellen LHF-Orbitale sind gut optimiert und erlauben eine effizienteBeschreibung sowohl angeregter Zust{\"a}nde als auch statischer Korrelationseffekte in MRCI und MRPT2-Ans{\"a}tzen. Weiterhin f{\"u}hrt die kompaktere Struktur der besetzten LHF-Orbitale zu einer besseren Beschreibung des kationischen Rumpfes von Rydbergzust{\"a}nden. Andererseits wurden zu beiden genannten Vorteilen auch jeweils ein Beispielmolek{\"u}l gefunden, in dem die Vorteile nicht zum Tragen kommen, und zu deren Beschreibung Orbitale aus HF- oder Standard-DFT-Methoden besser geeignet sind. Diese Beispiele zeigen, dass jeder Einzelfall f{\"u}r sich getestet werden muss, auch wenn die angeregten Zust{\"a}nde der meisten Molek{\"u}le sehr gut mit LHF-Orbitalen beschrieben werden k{\"o}nnen. Teil 2: Im zweiten Teil der vorliegenden Arbeit wurden die Paarungseigenschaften von Xanthin und Xanthinderivaten untersucht. Ziel dieses Teils war es, eine Erkl{\"a}rung f{\"u}r die unerwartet hohe Stabilit{\"a}t des Xanthin Alanyl-PNA Selbstpaarung zu finden. Weiterhin wurde untersucht, weshalb Xanthin, das in der DNA u.a. unter chemischem Stress gebildet wird, mutagene Fehlpaarungen mit der Pyrimidinbase Thymin eingehen kann. Stabilit{\"a}t der Xanthin Alanyl PNA: Zun{\"a}chst wurde durch den Vergleich experimenteller und berechneter 13C-NMR-Spektra das Regiosomer von Xanthin bestimmt, welches zu der ungew{\"o}hnlich hohen Stabilit{\"a}t der Xanthin-Xanthin-Selbstpaarung in Alanyl-PNA verantwortlich ist. Zur Untersuchung der Stabilit{\"a}t der Xanthin-Selbstpaarung wurde ein stark vereinfachendes Modell aufgestellt,in dem die Stabilit� at der PNA-Duplexe nur {\"u}ber die Energiebeitr{\"a}ge aus den Wasserstoffbr{\"u}cken (EDim) und der Basenstapelung (EStap) bestimmt wird. Die Dimerisierungs- und Stapelungsenergien unterschiedlicher Paarungen wurden mit DFT- und MP2-Methoden bestimmt. Solvenseffekte wurden {\"u}ber ein Kontinuummodell erfasst und der Einfluss des peptidischen R{\"u}ckgrats auf die Stapelungsgeometrie wurde durch Kraftfeldmethoden ber{\"u}cksichtigt. W{\"a}hrend die einzelnen Energiekomponenten aus den H-Br� ucken und der Basenstapelung keinen eindeutigen Zusammenhang zu den Schmelztemperaturen erkennen lassen, korreliert die Summe aus beiden linear mit den experimentell ermittelten Tm-Werten. Dies bedeutet, dass die Beitr{\"a}ge aus der Entropie, der molekularen Wasserumgebung und der R{\"u}ckgratspannung sich entweder aufheben oder f� ur alle behandelten Systeme sehr {\"a}hnlich sind. Die Stabilit{\"a}t der Xanthin-Xanthin- und die der 2,6-Diaminopurin-Xanthin-Paarung, ergibt sich durch einen erh{\"o}hten Stapelungsbeitrag der Purinpaarungen, w{\"a}hrend die Wasserstoffbr{\"u}cken der Xanthin Selbstpaarung nur wenig zur Stabilisierung des Xanthin-Xanthin und des Xanthin-Diaminopurin-Alanyl-PNA-Doppelstrangs beitragen. Paarungseigenschaften von N9-Xanthin: Zur Untersuchung der Paarungseigenschaften von N9-Xanthin wurden zun� achst H-verbr{\"u}ckte Homodimere von Xanthin untersucht. Hierbei wurden extreme Variationen in den Bindungsst{\"a}rken der einzelnen H-Br{\"u}cken gefunden, die sich zwischen -4 bis -11 kcal/mol in der Gasphase und -2.5 bis -5 kcal/mol im Solvens betragen. Durch Vergleich mit Modellsystemen konnte die starke Varianz der H-Br{\"u}ckenst{\"a}rke auf anziehende bzw. abstoßende sekund{\"a}re elektrostatische Wechselwirkungen zur{\"u}ckgef{\"u}hrt werden. Weiterhin wurde das Homodimer von Hypoxanthin untersucht, bei dem die H-Br{\"u}cken durch eine Erh{\"o}hung der Aromatizit{\"a}t im Pyrimidinring zus{\"a}tzlich verst{\"a}rkt werden, was zu einer deutlichen Stabilisierung des Dimers f{\"u}hrt. Elektronische Effekte m{\"u}ssen vor allem deshalb ber{\"u}cksichtigt werden, da sie im Unterschied zu rein elektrostatischen Effekten deutlich weniger von der Solvensumgebung beein usst werden. Mutagenit{\"a}t von Hypoxanthin und Xanthin: Zur Erkl{\"a}rung der Mutagenit{\"a}t von Hypoxanthin und Xanthin wurden verschiedene neutrale und anionische Watson-Crick Basenpaarungen von Hypoxanthin und Xanthin mit Pyrimidinbasen berechnet. Hierbei wurden u. a. auch tautomere und anionische Formen von Xanthin ber{\"u}cksichtigt. Zur Bewertung der erhaltenen Dimerisierungsenergien wurden die Paarungen danach klassifiziert, ob ihre Geometrien mit denen der kanonischen Basenpaarungen deckungsgleich sind, oder ob sie in einer verzerrten Watson-Crick Geometrie vorliegen, was die Einbaurate in die DNA aufgrund des r{\"a}umlichen Anspruchs der DNA-Polymerase vermindert. Die Rechnungen zeigen, dass Xanthin nur mit Cytosin Watson-Crick-Paarungen eingehen kann, welche jedoch nur sehr schwach gebunden sind. In der neutralen Form scheint eine dreiz{\"a}hnige Basenpaarung unter Beteiligung einer tautomeren Form des Xanthins etwas stabiler zu sein als die zweiz{\"a}hnige Paarung von Diketoxanthin mit Cytosin. Da die Dimerisierungsenergie sowohl der neutralen als auch der anionischen Basenpaarung nur wenig unter 0 kcal/mol liegt, ist der Einbau der Xanthin-Cytosin-Paarung in die DNA zwar aufgrund der g{\"u}nstigen Geometrie m{\"o}glich, wird aber nicht durch einen Energiebeitrag aus den H-Br{\"u}cken verst{\"a}rkt. Die im Vergleich zur Guanin-Cytosin Paarung deutlich geringere Aromatizit{\"a}t von Xanthin zu Cytosin ist im Einklang mit dem experimentellen Befund, dass die Cytosin-Xanthin Paarung deulich langsamer als die Guanin-Cytosin Paarungen in die DNA eingebaut werden. W{\"a}hrend die Rechnungen nur eine geringe Aromatizit{\"a}t von Xanthin zu Cytosin vorhersagen, scheint das Anion von Xanthin in der Lage zu sein, eine sehr stabile Basenpaarung mit Thymin einzugehen. Allerdings muss die Dimerisierungsenergie die schlechtere Anpassung in die Bindungstasche der DNA-Polymerase ausgleichen, da die Paarung in einer etwas verzerrten Watson-Crick Geometrie vorliegt. Insgesamt wird die Paarung daher nicht schneller in die DNA eingebaut, wie erwartet aufgrund der H-Br{\"u}ckenst{\"a}rken, stattdessen besitzt sie eine {\"a}hnliche Einbaurate wie die geometrisch g{\"u}nstigere aber weniger stabile Xanthin-Cytosin Paarung.},
  language  = {en}
}
@phdthesis{Noskov2003,
  author    = {Noskov, Andrey},
  title     = {Structural and functional studies of the Interleukin-5 receptor system},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8195},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The aim of current work was contribution to the long-term ongoing project on developing human IL-5 agonists/antagonists that intervene with or inhibit IL-5 numerous functions in cell culture and/or in animal disease models. To facilitate design of an IL-5 antagonist variant or low-molecular weight mimetics only capable of binding to the specific receptor alpha chain, but would lack the ability to attract the receptor common \&\#946;-chain and thus initiate receptor complex activation it is necessary to gain the information on minimal structural and functional epitopes. Such a strategy was successfully adopted in our group on example of Interleukin 4. To precisely localize minimal structural epitope it is essential to have structure of the ligand in its bound form and especially informative would be structure of complex of the ligand and its specific receptor alpha chain. For this purpose large quantities (tens of milligrams), retaining full biological activity IL-5 and extracellular domain of IL-5 specific receptor \&\#945;-chain were expressed in a bacterial expression system (E.coli). After successful refolding proteins were purified to 95-99\% Stable and soluble receptor:ligand complex was prepared. Each established purification and refolding procedures were subjected to optimization targeting maximal yields and purity. Produced receptor:ligand complex was applied to crystallization experiments. Microcrystals were initially obtained with a flexible sparse matrix screening methodology. Crystal quality was subsequently improved by fine-tuning of the crystallization conditions. At this stage crystals of about 800x150x30µm in size can be obtained. They possess desirable visible characteristics of crystals including optical clarity, smooth facecs and sharp edges. Crystals rotate plane polarized light reflecting their well internal organization. Unfortunately relative slimness and sometimes cluster nature of the produced crystals complicates acquisition of high-resolution dataset and resolution of the structure. With some of obtained crystals diffraction to a resolution up to 4{\AA} was observed.},
  subject      = {Interleukin 5},
  language  = {en}
}
@phdthesis{Majidifard2003,
  author    = {Majidifard, Mahmoud Reza},
  title     = {Biostratigraphy, lithostratigraphy, ammonite taxonomy and microfacies analysis of the Middle and Upper Jurassic of northeastern Iran},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8045},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The Middle and Upper Jurassic sedimentary successions of Alborz in northern Iran and Koppeh Dagh in northeastern Iran comprise four formations; Dalichai, Lar (Alborz) and Chaman Bid, Mozduran (Koppeh Dagh). In this thesis, the biostratigraphy, lithostratigraphy, microfacies, depositional environments and palaeobiogeography of these rocks are discussed with special emphasis on the abundant ammonite fauna. They constitute a more or less continuous sequence, being confined by two tectonic events, one at the base, in the uppermost part of the Shemshak Formation (Bajocian), the so-called Mid-Cimmerian Event, the other one at the top (early Cretaceous), the so-called Late-Cimmerian Event. The lowermost unit constitutes the uppermost member of a siliciclastic and partly continental depositional sequence known as Shemshak Formation. It contains a fairly abundant ammonite fauna ranging in age from Aalenian to early Bajocian. The following unit (Dalichai Formation) begins everywhere with a significant marine transgression of late Bajocian age. The following four sections were measured: The Dalichai section (97 m) with three members; the Golbini-Jorbat composite section (449 m) with three members of the Dalichai Formation (414 m) and two members of the Lar Formation (414 m); the Chaman Bid section (1556 m) with seven members, and the Tooy-Takhtehbashgheh composite section (567 m) with three members of the Chaman Bid Formation (567 m) and four members of the Mozduran Formation (1092 m). Altogether, 80 species of ammonites from the Dalichai and Chaman Bid formations belonging to 30 genera and 16 families are described. Among the taxa Phylloceratidae are most abundant, followed by Ataxioceratidae, Perisphinctidae, and Cardioceratidae. Pachyceratidae are the least common family. The ammonite fauna is of low diversity and is concentrated in several levels. Some of the ammonite genera and species are recorded from Iran for the first time. These include Pachyceras lalandei, Cardioceras praecordatum, Microbajocisphinctes sp., Geyssantia geyssanti, Larcheria schilli, Passendorferia sp., Sequeirosia sp., Phanerostephanus subsenex, Nothostephanus sp., Nannostephanus cf. subcomutus, Parawedekindia callomoni, Physodoceras sp., Extrenodites sp.. Biostratigraphically, thirty ammonite zones have been recognized for the Middle and Upper Jurassic successions at the four studied sections. Based on ammonites, the Dalichai Formation ranges from the Upper Bajocian to Callovian (Dalichai section) and from the Upper Bajocian to Lower Tithonian (Golbini-Jorbat section), the Chaman Bid Formation ranges from the ?Bathonian to Lower Tithonian (Chaman Bid section) and from the Upper Bajocian to Middle Kimmeridgian (Tooy-Takhtehbashgheh section), the Lar Formation ranges from the Middle to Upper Tithonian (Golbini-Jorbat section), and the Mozduran Formation from the Upper Kimmeridgian to ?Tithonian. Forty-four Microfacies types are briefly described. They were grouped into 16 facies associations, which then were interpreted in terms of their palaeoenvironments. They are part of a carbonate system consisting of a platform and adjacent slope to basin. Five major environments are represented: Tidal flat, shelf lagoon, and platform margin barrier as parts of the carbonate platform, and slope to basin representing open marine conditions. The sediments of the Dalichai and Chaman Bid formations are the slope and basinal sediments of the diachronous Lar and Mozduran formations, which formed an extensive carbonate platform in the Middle and Upper Jurassic.},
  subject      = {Chorasan},
  language  = {en}
}
@phdthesis{Musch2003,
  author    = {Musch, Patrick},
  title     = {Large-Scale Applications of Multi-Reference Methods in Chemistry and Development of a Multi-Reference Moller-Plesset Perturbation Theory Program},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7741},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The first part of this work focuses on the characterization of systems which complex electronic structures require the application of multi-reference methods. The anti-tumor efficacy of the natural product Neocarzinostatin is based on the formation of diradicals and causes DNA cleavage and finally cytolysis. Computations on model systems performed in the present work show the influence of structural features on the mode of action and the efficacy of this antitumor-antibiotic. The cyclization of systems related to the enyne-cumulene framework like the enyne-allenes was investigated earlier and relations to the more unusual class of enyne-ketenes are analyzed. The class of enyne-ketenes (and also the enyne-allenes) show a broad spectrum of possible intermediates (diradicals, zwitterions, allenes). The electronic structures of these intermediates are also possible for the (heteroatom substituted) 1,2,4-cyclohexatriene and a model for their energetic sequence based on high-level multi-reference computations is proposed. In all three projects the application of multi-reference approaches is necessary to obtain a comprehensive picture of the reactivity and electronic structure but also shows up the limits inherently existing in the currently available programs with respect to the size of the molecules. In the second part, algorithms for a multi-reference Moller-Plesset perturbation theory (MR-MP2) program, designed to perform large-scale computations, were developed and implemented. The MR-MP2 approach represents the most cost-effective multireference ansatz and requires an efficient evaluation of the Hamilton matrix for which an algorithm is designed to instantly recognize only non-vanishing matrix elements and to employ the recurring interaction patterns of the Hamilton matrix. The direct construction of the Hamilton matrix is additionally parallelized to work on cluster environments.},
  language  = {en}
}
@phdthesis{Kocher2003,
  author    = {Kocher, Nikolaus},
  title     = {Experimental charge density studies of highly polar bonds},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7614},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The main aim of this work was the classification of highly polar E-N (E = Al, Si, P) and Li-E' (E' = C, N, O) bonds in terms of ionic (closed-shell) or covalent (shared) interactions. To answer this question the experimentally determined electron density was analyzed using Bader's theory of 'Atoms in Molecules' (AIM). This allows a quantitative evaluation of properties derived from the electron density, such as the Laplacian, the ellipticitiy and the ratio of the highest charge concentration perpendicular to the bond path, to the largest charge depletion along the bonding vector. Most of these properties were monitored along the entire bonding region and not limited to the BCP as in former studies. The analyses are completed by the calculation of the electronic energy densities Hl at the BCPs and the integration of atomic basins also defined within the AIM theory. The electrostatic potential (ESP) was computed from the multipole parameters to reveal preferred reactive sites of the structures under investigation. Apart from that, the multipole formalism was applied to problematic crystal structures in order to open this method for twinned samples or those including disordered groups in the molecule.},
  subject      = {Elektronendichte},
  language  = {en}
}
@phdthesis{Attia2003,
  author    = {Attia, Mohamad Ibrahim},
  title     = {Design, synthesis and pharmacological evaluation of certain GABAB agonists},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7551},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Ziel dieser Arbeit war die Synthese von (RS)-5-Amino-3-aryl(methyl)-pentans{\"a}ure Hydrochloride, 3-Aminomethyl-5-chlor-benzols{\"a}ure Hydrochlorid und(RS)-4-Amino-3-(4´-ethynyl(jod)-phenyl)-butans{\"a}ure Hydrochloride und die Testung der pharmakologischen Aktivit{\"a}t dieser Verbindungen. Die synthetisierten Verbindungen wurden als GABAB-Rezeptor Agonisten, in einem auf Ca2+-Messungen basierenden Funktional-Assay (in vitro tsA Zellen mit GABAB1b/GABAB2/G\&\#945;q-z5 transfektiert), getestet und daraus ein Struktur-Aktivit{\"a}ts Modell abgeleitet. Im allgemein Teil dieser Arbeit wird ein {\"U}berblick, {\"u}ber die Neurotransmitter- Rezeptoren (Liganden gesteuerte Ionen-Kanal-Rezeptoren und G Protein-gekoppelte Rezeptoren) des zentralen Nervensystems und deren Agonisten und Antagonisten, gegeben. Eine ausf{\"u}hrliche Diskussion zur Synthesestrategie der Verbindungen der Zwischenstufen und der Ausgangsmaterialien wird in den Schemata 2-6 beschrieben. Die synthetisierten Verbindungen wurden als GABAB Agonisten gepr{\"u}ft. Zus{\"a}tzlich wurden diese im 3D Homologie Modell mit FlexiDock Programm gedockt. Daraus wurde ein Modell zur Voraussage der Aktivit{\"a}t von Analogen und Homologen des Baclofens abgeleitet. Letztendlich wurde ein Pharmakophor-Modell f{\"u}r GABAB Agonisten mit DISCO (DIStance COmparisons) Programm erstellt.},
  subject      = {Baclofen},
  language  = {en}
}
@phdthesis{Roth2003,
  author    = {Roth, Martin},
  title     = {Functional and developmental characterisation of matrix binding sites in decapentaplegic},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7542},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {In the last years it became evident that many cytokines do not only bind to their specific cell surface receptors but also interact with components of the extracellular matrix. Mainly in Drosophila, several enzymes were identified, that are involved in glycosaminoglycan synthesis. Mutations in these enzymes mostly result in disturbances of several signaling pathways like hedgehog, wingless, FGF or dpp. In most cases it was, due to these pleiotropic effects, not possible to examine the relevance of matrix interactions for single pathways. The aim of this work was to examine the relevance of matrix interactions for the TGF-ß superfamily member DPP. Based on the fact that DPP is highly homologous to human BMP-2, the basic N-terminus of mature DPP was mutated, which has been shown to contain a heparin-binding site in BMP-2. Thus, a wildtype variant (D-MYC), a deletion variant (D-DEL), which lacked the whole basic part of the N-terminus and a duplication variant (D-DUP), which contained a second copy of the basic core moitiv, were generated. In order to characterise the variants biochemically, they were expressed in E.coli and refolded in a bioactive form. In chicken limbbud assay, the deletion variant was much more active than the wildtype variant, comparable to data of BMP-2. By means of biacore mesurements with the immobilised ectodomain of the high affinity type I receptor thick veins, it could be demonstrated, that the variants differ only in matrix binding and not in their receptor affinity. Different matrix binding was shown by Heparin FPLC. The biological relevance of the matrix interaction of DPP was examined in transgenic flies. To allow expression of the different variants under the control of various Gal4 driver lines, they were cloned behind an UAS-promoter site. In early tracheal development, a strong dependence of DPP signaling on matrix binding was observed. While ectopic expression of the deletion variant caused only minor defects, the branching pattern was strongly disturbed by overexpression of wildtype and duplication variant. Ubiquitous expression of the variants in the wing imaginal disc caused overproliferation of the disc and expansion of the omb target gene expression. The extent of phenotypes correlated with the matrix binding ability of the variants. Corresponding disturbances of the wing vein pattern was observed in adult flies. By the crossing of different dpp allels, transheterozygous animals were created, that lack dpp only in imaginal discs. Expression of the variants under the control of a suitable dpp-Gal4 driver line revealed insights into the biological relevance of matrix binding on DPP gradient formation and specific target gene activation in wing imaginal discs. It was shown, that all variants were able to generate a functional DPP gradient with correct expression of the target genes omb and spalt. Again a correlation between extent of target gene domains and matrix binding ability of the corresponding variants was found. Thus by mutating the N-terminus of DPP, it could be shown that this is responsible for DPP`s matrix interaction. Also the relevance of matrix binding of DPP in different tissues was examined. It turned out, that the reorganisation of tracheal branching by DPP strongly depends on matrix interactions wheras the establishing of a gradient in wing imaginal discs depends only gradually on matrix interactions. Based on these data a model for the action of DPP/TGFßs as morphogens was established. While a deletion of matrix binding leads to a decrease in specific bioactivity of the cytokine, the latter is increased by additional matrix binding sites.},
  subject      = {Taufliege},
  language  = {en}
}
@phdthesis{Schulz2003,
  author    = {Schulz, Heidi},
  title     = {Towards a comprehensive description of the human retinal transcriptome: identification and characterization of differentially expressed genes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7278},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The human retina is a multilayered neuroectodermal tissue specialized in the transformation of light energy into electric impulses which can be transmitted to the brain where they are perceived as vision. Since the retina is easily accessible and functional aspects are directly recordable, the study of this tissue has been at the forefront of neuroscience research for over a century. Studies have revealed that the distinct functions of the retina require a large degree of differentiation which is achieved by the coordinated function of approximately 55 different cell types. The highly structured anatomy and the functional differentiation of the retina is a result of its distinctive transcriptome and proteome. Due to the complexity of the retina it has been difficult to estimate the number of genes actively transcribed in this tissue. Great efforts in the elucidation of retinal disease genes have led to the identification of 139 retina disease loci with 90 of the corresponding genes cloned thus far . In contrast to the success in the hereditary disorders, efforts to identify the genetic factors conferring manifestations known as age-related macular degeneration (AMD) have revealed sparse results. AMD is a retinal disease affecting a significant percentage of the older population. This disorder is likely due to exogenic as well as genetic factors. To further our understanding of retinal physiology and facilitate the identification of genes underlying retinal degenerations, particularly AMD, our efforts concentrated on the systematic analysis of the retinal transcriptome. Since approximately half of all retinal degeneration-associated genes identified to date are preferentially expressed in retina, it is plausible that the investigation of gene expression profiles and the identification of retina-expressed transcripts could be an important starting point for characterizing candidate genes for the retinal diseases. The expressed sequence tags approach included the assessment of all retinal expressed sequence tags (EST) clusters indexed in the UniGene database and of 1080 single-pass ESTs derived from an in-house generated human retina suppression subtracted hybridization (SSH) cDNA library. In total, 6603 EST clusters were evaluated during this thesis and detailed in-silico analysis was performed on 750 EST clusters. The expression of the genes was evaluated using reverse transcriptase-polymerase chain reaction (RT-PCR), followed by confirmation using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), as well as conventional and virtual Northern blot analysis. The expression profiling of 337 selected EST clusters led to the identification of 111 transcripts, of which 60 are specific or abundant to the retina, 3 are expressed at high levels in the retinal pigment epithelium (RPE), and 48 are expressed in brain as well as in retina. The EST approach used to select candidate transcripts allowed us to assess the effectiveness of the two available resources, the UniGene database and the retinal SSH (retSSH) cDNA library. From the results obtained, it is evident that the generation of suppression subtracted libraries to identify cell-specific transcripts constitutes the most straight-forward and efficient strategy. In addition to the high percentage of candidate genes that are identified from an SSH cDNA library, it has the added benefit that genes expressed at low levels can be identified. Furthermore, comparison of our retina-enriched gene set with previously published studies demonstrated only limited overlap of the identified genes further confirming the valuable source of retinal genes from our retinal SSH cDNA library. The effort of our and other groups has resulted in the establishment of the full-length coding sequence of 55 of the 111 genes uniquely or preferentially expressed in the retina. Using various methods such as bioinformatical analysis, EST assembly, cDNA library screening, and rapid amplification of cDNA ends (RACE) a number of genes were cloned in the scope of this thesis including C1orf32, C4orf11, C7orf9, C12orf7, C14orf29, DAPL1, and GRM7. Bioinformatic analyses and cDNA library screening were used to isolate the full-length cDNA sequence and determine the genomic organization of C7orf9, also identified as RFRP. This 1190 bp retina-specific transcript from chromosome 7p15.3 encodes a precursor protein for at least two small neuropeptides, referred to as RFRP-1 and RFRP-3. Since C7orf9 is localized in the critical region for dominant cystoid macular dystrophy (CYMD) its role in the pathology was investigated. Southern blot analysis and sequencing of samples from two affected individuals of the original pedigree used to localize the disease gene excluded the gene from involvement in this disease. Multiple isoforms of the C12orf7 gene were assembled from a number of clones identified from library screenings, PCR amplifications, and RACE experiments. The gene variants, transcribed from chromosome 12q13.13, have been found to be expressed exclusively in retina. Because of the multiple alternative splicing of the gene, we can only speculate about the nature of the protein it encodes. The longest transcript, which includes all six exons plus the last intervening sequence, encodes a 471 aa protein which contains a nuclear localization signal and five ankyrin repeats. The existence of many isoforms is also observed in mouse suggesting that they may have a relevant role in cellular physiology. Five novel splice variants of the glutamate metabotropic receptor 7 (GRM7) resulting from the use of alternative 3'-end exons were identified and characterized. One of the novel variants, GRM7_v3, encodes a 924 aa protein and is therefore the longest putative GRM7 protein reported to date. Even though they are not retina-specific, the isoforms are preferentially expressed in the nervous system. Although the functional properties of the specific carboxyl-termini are still unclear, it is known that axon targeting of GRM7_v1 is mediated by the last 60 aa of the protein. Hence the novel isoforms may direct the protein to specific subcellular localizations. The C1orf32 gene, preferentially expressed in retina, is organized in 10 exons and is transcribed from chromosome 1q24.1. Bioinformatic analyses of the 639 aa putative protein not only identified the mouse and rat orthologous genes but also the LISCH7 gene as a potential member of the same family. Since the LISCH7 protein has been shown to function as a low density lipoprotein receptor, the C1orf32 protein may be involved in retinal lipid homeostasis. Disturbances in lipid metabolism have been proposed as one of the pathways involved in AMD etiology. Thus, the role of C1orf32 in this complex disease should be investigated. Expression analyses of the death-associated protein-like 1 (DAPL1) gene revealed that it is expressed in both the retina and the RPE at high levels. The 552 bp transcript encodes a 107 aa putative protein and is transcribed from chromosome 2q24.1. In-silico analyses identified an additional 12 related proteins from various species which share high similarity constituting a novel protein family. The similarity to the death-associated-protein (DAP) is particularly interesting since this protein has been found to be indispensable for programmed cell death. Therefore, DAPL1 is an excellent candidate for retinal disease as apoptosis is generally the ultimate cause in retinal degeneration. The retina-specific C4orf11 and C14orf29 genes localized on chromosome 4q21.22 and 14q22.1, respectively, are both transcribed in more than one isoform. The encoded proteins do not contain any known domains but because of their retina-specific expression they may be important for proper retinal physiology. As part of the long-term goals of the project, several of the cloned genes are being genotyped to construct single nucleotide polymorphism (SNP) maps. Projects to investigate haplotype frequencies of candidate genes in large cohorts of controls and AMD patients are ongoing. Thus, by establishing a collection of 111 genes expressed exclusively or preferentially in the retina, the present work has laid the foundation for future research in retinal diseases.},
  subject      = {Netzhaut},
  language  = {en}
}
@phdthesis{Pavel2003,
  author    = {Pavel, Ioana-Emilia},
  title     = {Vibrational spectroscopy and density functional theory calculations, a powerful approach for the characterization of pharmaceuticals and new organometallic complexes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7186},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {In the current work, several well-known pharmaceuticals (1,4-dihydrazinophthalazine sulfate, caffeine, and papaverine hydrochloride) and new organometallic compounds (nickel(II) cupferronato complexes NiL2An, L = PhN2O2-, n = 1, A = o-phenanthroline (1), o,o'-bipyridine (2) and n = 2, A = H2O (3), o-NH2Py (4), o-C6H4(NH2)2 (5); silylene-bridged dinuclear iron complexes [Cp(OC)2Fe]2SiX2 (X = H (6), F (7), Cl (8), Br (9), I (10)); 3-silaoxetane 3,3-dimethyl-2,2,4,4-tetraphenyl-1-oxa-3-silacyclobutane (11) and 3-silathietane 3,3-dimethyl-2,2,4,4-tetraphenyl-1-sila-3-thiacyclobutane (12) compounds), which have successfully been characterized by using vibrational spectroscopy in conjunction with accurate density functional theory (DFT) calculations, are presented. The DFT computed molecular geometries of the species of interest reproduced the crystal structure data very well and in conjunction with IR and Raman measurements helped us to clarify the structures of the compounds, for which no experimental data were available; and this, especially for the new organometallic compounds, where the X-Ray analysis was limited by the non-availability of single crystals (3, 5, 10). Furthermore, a natural population analysis (NPA) and natural bond orbital (NBO) calculations together with a detailed analysis of the IR and Raman experimental as well as calculated spectra of the new organometallic compounds, allowed us to study some special bonding situations (1-12) or to monitor the structural changes observed with the change in temperature during the Raman experiments (11, 12). By combining these two methods (DFT and vibrational spectroscopy), the auspicious results obtained on the organometallic compounds 6-12 and overall in literature, made us confident of the power of theoretical calculations in aiding the interpretation of rich SERS spectra by solving some interesting issues. Consequently, the Raman and SERS spectra of well-known pharmaceuticals (1,4-dihydrazinophthalazine sulfate, caffeine, and papaverine hydrochloride) or new potentially biological active organometallic complexes (1-5), that were synthetized by our coworkers, were discussed with the assistance of the accurate results obtained from DFT calculations (structural parameters, harmonic vibrational wavenumbers, Raman scattering activities), and many previous incomplete assignments have been analyzed and improved. This allowed us to establish the vibrational behavior of these biological compounds near a biological artificial model at different pH values or concentrations (Ag substrate), taking into account that information about the species present under particular conditions could be of great importance for the interpretation of biochemical processes. The total electron density of molecules and the partial charges situated on selected atoms, which were determined theoretically by NPA, allowed us to establish the probability of different atoms acting as an adsorptive site for the metal surface. Moreover, a closer examination of the calculated orbitals of molecules brought further arguments on the presence or absence of the photoproducts at the Ag surface during the irradiation (1,4-dihydrazinophthalazine sulfate). Overall, the results provide a benchmark illustration of the virtues of DFT in aiding the interpretation of rich vibrational spectra attainable for larger polyatomic adsorbates by using SERS, as well as in furnishing detailed insight into the relation between the vibrational properties and the nature of the Ag substrate-adsorbate bonding. Therefore, we strongly believe that theoretical calculations will become a matter of rapidly growing scientific and practical interest in SERS.},
  subject      = {Arzneimittel},
  language  = {en}
}
@phdthesis{Drueppel2003,
  author    = {Dr{\"u}ppel, Kirsten},
  title     = {Petrogenesis of the Mesoproterozoic anorthosite, syenite and carbonatite suites of NW Namibia and their contribution to the metasomatic formation of the Swartbooisdrif sodalite deposits},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6987},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {During the Mesoproterozoic large volumes of magma were repeatedly emplaced within the basement of NW Namibia. Magmatic activity started with the intrusion of the anorthositic rocks of the Kunene Intrusive Complex (KIC) at 1,385-1,347 Ma. At its south-eastern margin the KIC was invaded by syenite dykes (1,380-1,340 Ma) and younger carbonatites (1,140-1,120 Ma) along ENE and SE trending faults. Older ferrocarbonatite intrusions, the 'carbonatitic breccia', frequently contain wallrock fragments, whereas subordinate ferrocarbonatite veins are almost xenolith-free. Metasomatic interaction between carbonatite-derived fluids and the neighbouring and incorporated anorthosites led to the formation of economically important sodalite deposits. Investigated anorthosite samples display the magmatic mineral assemblage of Pl (An37-75) ± Ol ± Opx ± Cpx + Ilm + Mag + Ap ± Zrn. Ilmenite and pyroxene are surrounded by narrow reaction rims of biotite and pargasite. During the subsolidus stage sporadic coronitic garnet-orthopyroxene-quartz assemblages were produced. Thermobarometry studies on amphiboles yield temperatures of 985-950°C whereas the chemical composition of coronitic garnet and orthopyroxene indicate a subsolidus re-equilibration of the KIC at conditions of 760 ± 100°C and 7.3 ± 1 kbar. In the syenites Kfs, Pl, Hbl and/or Cpx crystallized first, followed by a second generation of Kfs, Hbl, Fe-Ti oxides and Ttn. Crystallization of potassium feldspar occurred under temperatures of 890-790°C. For the crystallization of hastingsite pressures of 6.5 ± 0.6 kbar are obtained. In order to constrain the source rocks of the two suites, oxygen isotope analyses of feldspar as well as geochemical bulk rock analyses were carried out. In case of the anorthosites, the general geochemical characteristics are in excellent agreement with their derivation from fractionated basaltic liquids, with the d18O values (5.88 ± 0.19  per mille) proving their derivation from mantle-derived magmas. The results obtained for the felsic suite, provide evidence against consanguinity of the anorthosites and the syenites, i.e. (1) compositional gaps between the geochemical data of the two suites, (2) trace element data of the felsic suite points to a mixed crustal-mantle source, (3) syenites do not exhibit ubiquitous negative Eu-anomalies in their REE patterns, which would be expected from fractionation products of melts that previously formed plagioclase cumulates and (4) feldspar d18O values from the syenites fall in a range of 7.20-7.92  per mille, which, however, is about 1.6  per mille higher than the average d18O of the anorthosites. Conformably, the crustal-derived felsic and the mantle-derived anorthositic suite are suggested to be coeval but not consanguineous. Their spatial and temporal association can be accounted for, if the heat necessary for crustal melting is provided by the upwelling and emplacement of mantle-derived melts, parental to the anorthosites. In order to constrain the source of the 1,140-1,120 Ma carbonatites and to elucidate the fenitizing processes, which led to the formation of the sodalite, detailed mineralogical and geochemical investigations, stable isotope (C,O,S) analyses and fluid inclusion measurements (microthermometrical studies and synchrotron-micro-XRF analyses) have been combined. There is striking evidence that carbonatites of both generations are magmatic in origin. They occur as dykes with cross-cutting relationships and margins disturbed by fenitic aureoles, and contain abundant flow-oriented xenoliths. The mineral assemblage of both carbonatite generations of Ank + Cal + Ilm + Mag + Bt ± Ap ± pyrochlore ± sulphides in the main carbonatite body and Ank + Cal + Mag ± pyrochlore ± rutile in the ferrocarbonatite veins, their geochemical characteristics and the O and C isotope values of ankerite (8.91 to 9.73 and -6.73 to -6.98, respectively) again indicate igneous derivation, with the 18O values suggesting minor subsolidus alteration. NaCl-rich fluids, released from the carbonatite melt mainly caused the fenitization of both, the incorporated and the bordering anorthosite. This process is characterized by the progressive transformation of Ca-rich plagioclase into albite and sodalite. Applying conventional geothermobarometry combined with fluid-inclusion isochore data, it was possible to reconstruct the P-T conditions for the carbonatite emplacement and crystallization (1200-630°C, 4-5 kbar) and for several mineral-forming processes during metasomatism (e.g. formation of sodalite: 800-530°C). The composition and evolutionary trends of the fenitizing solution were estimated from both the sequence of metasomatic reactions within wallrock xenoliths in the carbonatitic breccia and fluid inclusion data. The fenitizing solutions responsible for the transformation of albite into sodalite can be characterised as of NaCl-rich aqueous brines (19-30 wt.\% NaCl eq.), that contained only minor amounts of Sr, Ba, Fe, Nb, and LREE.},
  subject      = {Namibia <Nordwest>},
  language  = {en}
}
@phdthesis{AbdelRahman2003,
  author    = {Abdel Rahman, Faisal Mirghani},
  title     = {Systematic analysis of genes expressed in the retinal pigment epithelium (RPE) and identification of candidates for genetic susceptibility to age-related macular degeneration (AMD)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7053},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Age related macular degeneration (AMD) is the leading cause of visual impairment in the elderly and the major cause of blindness in the developed world. To date, the molecular mechanisms underlying the disease are not well understood although in recent years a primary involvement of the retinal pigment epithelium (RPE) has become evident. The aim of the present study is to systematically analyse genes which are differentially expressed in the RPE, and to assess their possible association with mechanisms and pathways likely to be related to retinal disease, in particular AMD. Towards this goal, 2379 expressed sequence tags (ESTs) were established from an inhouse generated RPE cDNA library. This library was constructed by using the suppression subtraction hybridization (SSH) technique which normalises redundant sequences and ensures enrichment of rare transcripts. In a first phase, 1002 ESTs were sequenced and subjected to comprehensive alignment with public nucleotide and protein databases. A search of the 1002 ESTs against the human genome draft sequence yielded 168 known genes, 51 predicted genes, 15 unknown transcripts and 41 clones with no significant similarity. Reverse Northern blot hybridization was performed for 318 EST clusters to identify abundantly expressed genes in the RPE and to prioritize subsequent analyses. Representative clones were spotted onto a nylon membrane and hybridized with cDNA probes of driver (heart and liver) and tester (RPE) used in the cDNA library construction. Subsequently, 107 EST clusters were subjected to Northern blot hybridizations. These analyses identified 7 RPE-specific, 3 retina-specific, 7 RPE/retina-specific, and 7 tissue restricted transcripts, while 29 EST clusters were ubiquitously expressed, and evaluation was not possible for another 54 EST clusters. Of the 24 transcripts with specific or restricted expression, 16 clones were selected for further characterization. The predicted gene MGC2477 and 2 novel isoforms of the human transient receptor potential cation channel, subfamily M, member 3 (TRPM3) were cloned and further described in detail. In addition, polymorphic variations for these 2 genes as well as for the human MT-Protocadherin gene were determined. For MGC2477, 15 single nucleotide polymorphisms (SNPs) were identified, with 13 having a frequency of the minor allele greater than 20\%. 10 of the 15 SNPs have not been reported in so far in public SNP repertoires. Partial assessment of the TRPM3 gene yielded 35 SNPs. Of these, 30 (85.7\%) were highly frequent (0.17-0.5\%), and 14 (40\%) were novel. The MT-Protocadherin gene revealed 35 SNPs, including 28 (80\%) with high frequency of the minor allele. 23 (65.7\%) were novel SNPs. These SNPs will be used to construct the most common haplotypes. These will be used in case/control association studies in 400 AMD patients and 200 ethnically and aged matched controls to assess a possible contribution of these genes in the etiology of AMD.},
  subject      = {Senile Makuladegeneration / Pigmentepithel / Genexpression},
  language  = {en}
}
@phdthesis{Nedvetsky2003,
  author    = {Nedvetsky, Pavel I.},
  title     = {Regulation of the nitric oxide receptor, soluble guanylyl cyclase},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-7046},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Soluble guanylyl cyclase (sGC) is the best established receptor for nitric oxide (NO) and regulates a great number of important physiological functions. Surprisingly, despite the wellappreciated roles of this enzyme in regulation of vascular tone, smooth muscle cell proliferation, platelet aggregation, renal sodium secretion, synaptic plasticity, and other functions, extremely little is known about the regulation of sGC activity and protein levels. To date, the only well-proven physiologically relevant sGC regulator is NO. In the present study, some additional possibilities for sGC regulation were shown. Firstly, we evaluated the ability of different NO donors to stimulate sGC. Significant differences in the sGC stimulation by SNP and DEA/NO were found. DEA/NO stimulated sGC much stronger than did SNP. Interestingly, no correlation between the sGC protein and maximal activity distribution was found in rat brain regions tested, suggesting the existence of some additional regulatory mechanisms for sGC. The failure of SNP to stimulate sGC maximally might be one of the reasons why the lack of correlation between the distribution of sGC activity and proteins in brain was not detected earlier. Prolonged exposure of endothelial cells to NO donors produced desensitization of the cGMP response. This desensitization cannot be explained by increased PDE activity, since PDE inhibitors were not able to prevent the NO donor-induced decrease of the maximal cGMP response in endothelial cells. The failure of SH-reducing agents to improve the cGMP response after its desensitization by NO suggests that a SH-independent mechanism mediates NO effects. Demonstration that the potency of the recently described activator of oxidized (heme-free) sGC, BAY58-2667, to stimulate sGC increases after prolonged exposure of the cells to an NO donor, DETA/NO, suggests that oxidation of heme may be a reason for NOinduced desensitization of sGC and decrease in sGC protein level. Indeed, the well-known heme-oxidizing agent ODQ produces a dramatic decrease in sGC protein levels in endothelial cells and BAY58-2667 prevents this effect. Although the mechanism of sGC activation and stabilization by BAY58-2667 is unknown, this substance is an interesting candidate to modulate sGC under conditions where sGC heme iron is oxidized. Very little is known about regulation of sGC by intracellular localization or translocation between different intracellular compartments. In the present study, an increase in sGC sensitivity to NO under membrane association was demonstrated. Treatment of isolated lung with VEGF markedly increased sGC in membrane fractions of endothelial cells. Failure of VEGF to stimulate sGC membrane association in cultured endothelial cells allows us to propose a complex mechanism of regulation of sGC membrane association and/or a transient character of sGC membrane attachment. A very likely mechanism for the attachment of sGC to membranes is via sGCinteracting proteins. These proteins may participate also in other aspects of sGC regulation. The role of the recently described sGC interaction partner, Hsp90, was investigated. Shortterm treatment of endothelial cells with an Hsp90 inhibitor does not affect NO donor or calcium ionophore-stimulated cGMP accumulation in the cells. However, inhibition of Hsp90 results in a rapid and dramatic decrease in sGC protein levels in endothelial cells. These effects were unrelated to changes in sGC transcription, since inhibition of transcription had much slower effect on sGC protein levels. In contrast, inhibitors of proteasomes abolished the reduction in sGC protein levels produced by an Hsp90 inhibitor, suggesting involvement of proteolytic degradation of sGC proteins during inhibition of Hsp90. All these data together suggest that Hsp90 is required to maintain mature sGC proteins. In conclusion, in the present study it was demonstrated that multiple mechanisms are involved in the regulation of sGC activity and its sensitivity to NO. Oxidation of sGC heme by NO seems to be one of the mechanisms for negative regulation of sGC in the presence of high or prolonged stimulation with NO. Another possible means of regulating sGC sensitivity to NO is via the intracellular translocation of the enzyme. It has been also demonstrated here that attachment of sGC to the membrane fraction results in an apparent increase in the enzyme sensitivity to NO. Additionally, Hsp90 was required to maintain sGC protein in endothelial and other cell types. However, we could not find any acute affect of Hsp90 on sGC activity, as reported recently. All these findings demonstrate that the regulation of sGC activity and protein level is a much more complex process than had been assumed earlier.},
  subject      = {Guanylatcyclase},
  language  = {en}
}
@phdthesis{FadlElMola2003,
  author    = {Fadl El Mola, Faisal Mohamed},
  title     = {Bioinformatic and molecular approaches for the analysis of the retinal pigment epithelium (RPE) transcriptome},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6877},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {There is substantial interest in the identification of genes underlying susceptibility to complex human diseases because of the potential utility of such genes in disease prediction and therapy. The complex age-related macular degeneration (AMD) is a prevalent cause of legal blindness in industrialized countries and predominantly affects the elderly population over 75 years of age. Although vision loss in AMD results from photoreceptor cell death in the central retina, the initial pathogenesis likely involves processes in the retinal pigment epithelium (RPE) (Liang and Godley, 2003). The goal of the current study was to identify and characterize genes specifically or abundantly expressed in the RPE in order to determine more comprehensively the transcriptome of the RPE. In addition, our aim was to assess the role of these genes in AMD pathogenesis. Towards this end, a bovine cDNA library enriched for RPE transcripts was constructed in-house using a PCR-based suppression subtractive hybridization (SSH) technique (Diatchenko et al., 1996, 1999), which normalizes for sequence abundance and achieves high enrichment for differentially expressed genes. CAP3 (Huang and Madan, 1999) was used to assemble the high quality sequences of all the 2379 ESTs into clusters or singletons. 1.2\% of the 2379 RPE-ESTs contains vector sequences and was excluded from further analysis. 5\% of the RPE-ESTs showed homology to multipe chromosomes and were not included in further assembly process. The rest of the ESTs (2245) were assembled into 175 contigs and 509 singletons, which revealed approximately 684 unique genes in the dataset. Out of the 684, 343 bovine RPE transcripts did not align to their human orthologues. A large fraction of clones were shown to include a considerable 3´untranslated regions of the gene that are not conserved between bovine and human. It is the coding regions that can be conserved between bovine and human and not the 3' UTR (Sharma et al., 2002). Therefore, more sequencing from the cDNA library with reclustering of those 343 ESTs together with continuous blasting might reveal their human orthologoues. To handle the large volume of data that the RPE cDNA library project has generated a highly efficient and user-friendly RDBMS was designed. Using RDBMS data storage can be managed efficiently and flexibly. The RDBMS allows displaying the results in query-based form and report format with additional annotations, links and search functions. Out of the 341 known and predicted genes identified in this study, 2 were further analyzed. The RPE or/and retina specificity of these two clones were further confirmed by RT-PCR analysis in adult human tissues. Construction of a single nucleotide polymphism (SNP) map was initiated as a first step in future case/control association studies. SNP genotyping was carried out for one of these two clones (RPE01-D2, now known as RDH12). 12 SNPs were identified from direct sequencing of the 23.4-kb region, of which 5 are of high frequency. In a next step, comparison of allele frequencies between AMD patients and healthy controls is required. Completion of the expression analysis for other predicted genes identified during this study is in progress using real time RT-PCR and will provide additional candidate genes for further analyses. This study is expected to contribute to our understanding of the genetic basis of RPE function and to clarify the role of the RPE-expressed genes in the predisposition to AMD. It may also help reveal the mechanisms and pathways that are involved in the development of AMD or other retinal dystrophies.},
  subject      = {Senile Makuladegeneration},
  language  = {en}
}
@phdthesis{KittisakSripha2003,
  author    = {Kittisak Sripha,},
  title     = {NOVEL HETEROCYCLIC RING SYSTEMS DERIVED FROM CARACURINE V AS LIGANDS FOR THE ALLOSTERIC SITE OF MUSCARINIC M 2 RECEPTORS},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6841},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Die vorliegende Arbeit befasst sich mit dem Gebiet allosterischer Modulation des muscarinischen M2 Rezeptors. Allosterische Liganden beeinflussen das Bindungsverhalten eines orthosterischen Liganden (Agonisten oder Antagonisten) an die klassische Bindungsstelle des muscarinischen Rezeptors, indem sie seine Affinit{\"a}t entweder erh{\"o}hen(positive Kooperativit{\"a}t) oder erniedrigen (negative Kooperativit{\"a}t). Die allosterische Bindungsstelle befindet sich extrazellul{\"a}r am Eingang der Rezeptor-Bindungstasche. Sie ist weniger konserviert als die orthosterische Bindungsdom{\"a}ne, die tiefer im Rezeptorkanal zwischen den sieben transmembranalen Dom{\"a}nen lokalisiert ist. Demzufolge ist die Entwicklung subtyp-spezifischer allosterisch wirkenden Liganden leichter als subtypspezifischer Agonisten oder Antagonisten. Die Subtypselektivit{\"a}t kann dar{\"u}ber hinaus {\"u}ber unterschiedliche Kooperativit{\"a}ten zwischen dem orthosterischen und allosterischen Liganden an verschiedenen muscarinischen Subtypen erreicht werden. Ein am M1-Rezeptor mit Acetylcholin positiv kooperativer allosterer Modulator, der sich an anderen muscarinischen Subtypen neutral kooperativ verh{\"a}lt, k{\"o}nnte z.B. f{\"u}r die Therapie von Morbus Alzheimer eingesetzt werden. Bisquart{\"a}re Ammoniumsalze des Strychnos-Alkaloids Caracurin-V geh{\"o}ren zu den potentesten allosterischen M2-Liganden. Die relative Stellung der aromatischen Indolringe und der Abstand zwischen den positiv geladenen Stickstoffatomen (ca. 10) in dem sehr starren Caracurin-V-Ringsystem definieren den Pharmakophor f{\"u}r potente allosterische Modulatoren. Caracurin-V-Salze sind strukturell sehr verwandt mit den starken Muskelrelaxantien Toxiferin-I und Alcuronium und besitzen vermutlich selbst neuromuskul{\"a}r-blockierende Eigenschaften, was ihre Anwendung in der pharmakologischen Forschung einschr{\"a}nken w{\"u}rde. Reduktion des Caracurin-V-Ringsystems auf die wesentlichen Pharmakophorelemente k{\"o}nnte zu allosterisch wirksamen Verbindungen mit vernachl{\"a}ssigbarer muskelrelaxierender Wirkung f{\"u}hren. Ziel dieser Arbeit war die Synthese und pharmakologische Testung von Derivaten eines neuen, von Caracurin V abgeleiteten, heterocyclischen Ringsystems. Das neue gew{\"u}nscht 6,7,14,15-Tetrahydro[1,5]diazocino[1,2-a:6,5-a]-diindole-Ringsystem(6) wurde in einer intermolekularen N-Alkylierung von zwei Molek{\"u}len Bromethylindol 5 aufgebaut. Die Ausgangsverbindung 5 konnte aus dem Indolylessigs{\"a}uremethylester 3 durch Reduktion der Estergruppe zum Alkohol und anschließende Substitution durch Brom dargestellt werden. Der bekannte Ester 3 wurde ausgehend von Tryptamin erhalten. Die dreistufige Synthese umfasste N-Dibenzylierung, Einf{\"u}hrung der Malonestergruppe am C-2 von Indol und anschließende Demethoxycarbonylierung. Die Totalsynthese des neuen Pentacyclus ist im Schema 24 dargestellt. Die 3D-Struktur des neuen Ringger{\"u}stes konnte mit Hilfe von NMR-Spektroskopie und semiempirischen Rechnungen (AM1) aufgekl{\"a}rt werden. Verbindung 6 liegt in L{\"o}sung in einer verdrehten Wanne-Konformation mit unsymmetrisch angeordneten Seitenketten vor. Um den Einfluss der Seitenkettenl{\"a}nge des neuen Ringsystems auf die allosterische Wirksamkeit zu untersuchen, war es geplannt, die Ethylamin-Gruppen durch Methylamin-Einheiten zu ersetzen. Der entsprechende Syntheseplan bestand darin, das unsubstituierte Ringsystem in einer doppelten Mannich-Reaktion zu aminomethylieren. Der Ausgangsstoff f{\"u}r die Dimerisierung, Bromethylindol 32, wurde aus Indol-2-carbons{\"a}ure hergestellt. Die Synthese umfasste folgende Reaktionsschritte: Reduktion der Carboxylgruppe und Benzoylierung des resultierenden Alkohols, nucleophile Substitution mit Kaliumcyanid, alkalische Hydrolyse des Cyanids zu Indolacetessigs{\"a}ure, erneute Reduktion zum Alkohol und abschließende Substitution mit Brom. Da Dimerisierungsversuche von 32 nur zur Bildung des HBr-Eliminierungsproduktes 33 f{\"u}hrten, wurde das entsprechende Tosylat als Ausgangsstoff eingesetzt. {\"U}berraschenderweise entstand nicht das erwartete Diazocinodiindol-Ringger{\"u}st, sondern ausschließlich ein isomeres, noch nicht bekanntes 6,7,14,15-Tetrahydro-15aH-azocino[1,2-a:6,5-b]diindol-Ringsystem 35. Die Bildung des neuen unsymmetrischen Ringsystems ist auf den ambidenten Charakter des Indolylanions zur{\"u}ckzuf{\"u}hren, das entweder am Sticksoff oder an C3 alkyliert werden kann. Umsetzung von 35 nach Mannich lieferte das bisaminoalkylierte Produkt 37, neben einer kleinen Menge der monoalkylierten Verbindung 36. Die Totalsynthese des zweiten Ringsystems ist im Schema 25 dargestellt. Um potentere Verbindungen zu erhalten, wurden beide Endstufen 6 bzw. 37 mit Methyliodid zu 14 bzw. 38 quaternisiert. 37 wurde zus{\"a}tzlich mit Allylgruppen zu 39 substituiert. Die pharmakologische Testung von 14, 37, und 38 erfolgte {\"u}ber Radioligandbindungsstudien an Membransuspensionen der Herzventrikel des Hausschweins. Der allostere Effekt der Testverbindungen wurde {\"u}ber die Hemmung der Dissoziation von [3H]-N-Methylscopolamin([3H]-NMS) von den damit ges{\"a}ttigten Rezeptoren gemessen. Die erhaltenen EC50,diss-Werte geben die Konzentration des allosteren Modulators an, bei der die [3H]-NMS-Dissoziation auf die H{\"a}lfte des Kontrollwertes reduziert ist. Sie sind ein Maß f{\"u}r die Affinit{\"a}t der Testsubstanzen zur allosterischen Bindungsstelle des M2 Rezeptors. F{\"u}r die einzige Verbindung mit dem Diazocinodiindole-Ringsystem 14 wurde ein EC50,diss-Wert von 54 nM gemessen. Da 14 {\"u}ber vier Benzylsubstituenten verf{\"u}gt, kann seine Bindungsaffinit{\"a}t am besten mit der von Dibenzylcaracurinium-Dibromid verglichen werden, die ganz {\"a}hnlich ist (69 nM). Aufgrund der Tatsache, dass die Verkleinerung des NSubstituenten am Caracurin-V-Ger{\"u}st zur erheblichen Steigerung der allosterischen Potenz f{\"u}hrte, ist zu erwarten, dass der Austausch der volumin{\"o}sen Benzylgruppen von 14 durch z.B. Methyl- oder Allylsubstituenten, eine deutliche Affinit{\"a}tssteigerung bewirken w{\"u}rde. Damit scheint die allosterische Potenz des neuen Ringsystems mindestens genauso gut zu sein, wie die von Caracurin V. Die beiden Vertreter des Azocinodiindol-Ringsystems, 38 und 39, sind bereits mit den Gruppen substituiert, die die beste allosterische Potenz bei dem Caracurin-V-Ringsystem zeigten (Methyl- und Allyl). Ihre EC50,diss-Werte (35 nM f{\"u}r 38, 48 nM f{\"u}r 39) sprechen jedoch f{\"u}r eine ca. 4-fach schw{\"a}chere Bindungsaffinit{\"a}t als die der entsprechenden Caracurine, was vermutlich auf einen anderen Abstand zwischen den quart{\"a}ren Stickstoffatomen und eine andere relative Stellung der Indolaromaten in den beiden Ringsystemen zur{\"u}ckzuf{\"u}hren ist. Anders als die entsprechenden Caracurin-V-Salze, sind 38 und 39 negativ kooperativ mit dem Antagonisten [3H]NMS. Zusammenfassend l{\"a}sst sich feststellen, dass von den beiden neu synthetisierten heterocyclischen Ringsystemen das direkt von Caracurin V abgeleitete Tetrahydro- [1,5]diazocino[1,2-a:6,5-a]diindol eine bessere und vielversprechende Leitstruktur f{\"u}r die Entwicklung neuer potenter allosterischen Liganden des M2-Rezeptors darstellt. Weitere synthetische Arbeiten an dem Ringsystem wie z.B. Variation des Sticksstoffsubstituenten und der Seitenkettenl{\"a}nge sollten zu einer Steigerung der Bindungsaffinit{\"a}t in den subnanomolaren Bereich f{\"u}hren. Dar{\"u}ber hinaus sind die Ergebnisse der pharmakologischen Testung an dem muskul{\"a}ren Typ des nicotinischen Acetylcholinrezeptors abzuwarten.},
  subject      = {Muscarinrezeptor},
  language  = {en}
}
@phdthesis{GarciaArguinzonis2003,
  author    = {Garc{\´i}a Arguinzonis, Ma{\´i}sa In{\´e}s},
  title     = {Analysis of signal transduction pathways and the cytoskeleton in VASP-deficient cell lines and mouse models},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6195},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The mammalian Vasodilator Stimulated Phosphoprotein (VASP) is a founding member of the Ena/VASP family of proteins that includes Drosophila Enabled (ena), the mammalian Ena homologue (Mena) and the Ena-VASP-like protein (Evl). VASP was initially discovered and characterized as a substrate for cGMP- and cAMP-dependent protein kinases (cGKs and cAKs). Ena/VASP proteins are involved in Actin-filament formation, plasma membrane protrusion, acceleration of Actin-based motility of Listeria and the establishment of cell-cell adhesion. Moreover, Ena/VASP proteins have been implicated as inhibitory factors in repulsive axon guidance and inhibition of plasma membrane activity and random motility in fibroblast. In order to study the physiological function of VASP, VASP-deficient mice had been generated in the laboratory by homologous recombination. VASP-/- mice showed hyperplasia of megakaryocytes in the bone marrow and spleen and a two-fold increase in thrombin- and collagen-induced platelet activation. To further investigate the cellular function of VASP, I established cardiac fibroblast cell lines derived from both wild type and VASP-/- mice. Both cell lines presented similar growth rates and normal contact dependent-growth inhibition but showed differences in morphology, migration and adhesion. Adherent VASP-/- cells, despite normal Mena and Evl expression levels, were highly spread. VASP-/- cells covered about twice the substrate surface area as wild type cells, while the cell volumes were unchanged. This shape difference suggests that VASP is involved in the regulation of spreading. Since the small GTPases Rac and Cdc 42 and their effector p21-activated kinase (Pak) are key regulators of lamellipodia formation and cell spreading, I analyzed this signalling pathway in VASP-/- cells stimulated with Platelet Derived Growth Factor-BB (PDGF-BB) or fetal calf serum. In wild type cells Rac and Pak were rapidly and transiently activated by PDGF or serum; however, in the absence of VASP both Rac and Pak activation was dramatically prolonged. The Rac/Pak pathway is known to play an essential role in cell motility. VASP deficient cells showed compromised migration and reorientation in a wound healing assay, probably due to enhanced Rac activity. The spreading phenotype, compromised migration and the effect observed on the Rac and Pak activities were reverted in VASP-/- cells stably transfected with full lenght human VASP, indicating a VASP dependent modulation of the Rac/Pak pathway and Rac/Pak regulated processes. Moreover, adhesion and detachment of VASP-deficient cells were significantly slower when compared to wild type cells. Preincubation of VASP+/+ cells with a cGMP analog accelerated adhesion. This acceleration did not take place in the VASP-/- cells, suggesting a VASP dependent effect. The second part of this work focused on VASP function in platelets. On the one hand I investigated the possibility of VASP-dependent Rac regulation in mouse platelets. Murine platelets are a good model for studying Rac regulation since they express high levels of VASP but not Mena/Evl and since VASP-deficient platelets show an increased platelet activation. Rac was activated by platelet agonists which was inhibited by preincubation with cGMP and cAMP analogs. Initial results which need to be extended showed that the cGMPcaused inhibition of Rac activation was VASP-dependent. Finally, in vivo platelet adhesion (platelet-vessel wall interactions) was studied using VASP-deficient mice. These studies demonstrated in-vivo that VASP down regulates platelet adhesion to the vascular wall under both physiological and pathophysiological conditions.},
  subject      = {Vasodilatator-stimuliertes Phosphoprotein},
  language  = {en}
}
@phdthesis{Schulte2003,
  author    = {Schulte, Valerie},
  title     = {In vitro and in vivo studies on the activating platelet collagen receptor glycoprotein VI in mice},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6564},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The work summarized here focused on the characterization of the murine platelet collagen receptor glycoprotein (GP) VI and was performed to evaluate its potential as an antithrombotic target. The first mAb against (mouse) GPVI, JAQ1, was generated and used to demonstrate that GPVI requires the FcRgamma-chain for its expression and function and that this receptor is the central molecule in collagen-induced platelet activation. Blocking the major collagen binding site on GPVI with JAQ1 revealed the presence of a second activatory epitope within collagen. Additionally, the collagen receptor integrin alpha2beta1 was found to be required for activation via this second pathway but not to be essential for collagen-induced activation of normal platelets. In studies with mice expressing reduced levels of the GPVI-FcRgamma-complex, differential responses to GPVI ligands were observed. Most importantly, the striking difference between platelet responses to collagen and the GPVI specific synthetic collagen related peptide (CRP) confirmed the supportive role of other collagen receptor(s) on platelets. Irrespective of yet undefined additional receptors, studies with mice deficient in GPVI (FcRgamma-chain) or alpha2beta1 showed that GPVI, but not alpha2beta1 is essential for platelet-collagen interaction. Based on these results, the model of platelet attachment to collagen was revised establishing GPVI as the initial activating receptor which upregulates the activity of integrins, thus enabling firm attachment of platelets to the ECM. While the mAb JAQ1 had only limited inhibitory effects on collagen-induced activation in vitro, its in vivo application to mice resulted in completely abolished platelet responses to collagen and the GPVI specific agonists CRP and convulxin. This effect was found to be due to antibody-induced irreversible down-regulation of GPVI on circulating platelets for at least two weeks. Further studies revealed that GPVI depletion occurs independently of the targeted epitope on the receptor and does not require the divalent form of IgG as it was also induced by mAbs (JAQ2, JAQ3) or the respective Fab fragments directed against epitopes distinct from the major collagen binding site. The internalization of GPVI in vivo resulted in a long-term protection of the mice from lethal collagen-dependent thromboembolism whereas it had only moderate effects on the bleeding time, probably because the treatment did not affect other activation pathways. These results establish GPVI as a potential pharmacological target for the prevention of ischemic cardiovascular diseases and may open the way for a completely new generation of antithrombotics.},
  subject      = {Maus},
  language  = {en}
}
@phdthesis{Mody2003,
  author    = {Mody, Karsten},
  title     = {Patterns of arthropod distribution and determinants of arthropod assemblage composition in a natural West African savannah},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6202},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {This study investigated patterns of arthropod community organisation and the processes structuring these communities on a range of different tree species in a natural West African savannah (Como{\´e} National Park, C{\^o}te d'Ivoire). It described and analysed patterns of arthropod distribution on the level of whole communities, on the level of multiple-species interactions, and on the level of individual insect species. Community samples were obtained by applying (i) canopy fogging for mature individuals of three tree species (Anogeissus leiocarpa, Burkea africana, Crossopteryx febrifuga) and (ii) a modified beating technique allowing to sample the complete arthropod communities of the respective study plants for medium-sized (up to 3 m) individuals of two other species (Combretum fragrans, Pseudocedrela kotschyi). General information on ant-plant interactions was retrieved from ant community comparisons of the mature savannah trees. In addition, ant-ant, ant-plant and ant-herbivore interactions were studied in more detail considering the ant assemblages on the myrmecophilic tree Pseudocedrela kotschyi. Herbivore-plant interactions were investigated on a multiple-species level (interrelationships between herbivores and Pseudocedrela trees) and on a species level (detailed studies of interrelationships between herbivorous beetles and caterpillars and the host tree Combretum fragrans). The studies on individual herbivore species were complemented by a study on an abundant ant species, clarifying not only the relationship between host plant and associated animal but allowing also to look at interactive (competitive) aspects of community organisation. The study demonstrated for the first time that (i) the structure of beetle communities on tropical trees can be strongly dependent on the host tree species, (ii) individual trees can host specific arthropod communities whose characteristic structure is stable over years and is strongly determined by the individual tree's attributes, (iii) ants can express a pronounced fidelity to single leaves as foraging area and can thereby determine distribution patterns of other ants, (iv) intraspecifically variable palatability of plants for insect herbivores can be stable over years and can influence the distribution of herbivores that can distinguish between individual hosts according to palatability and (v) intraspecific host plant change can positively affect fitness of herbivores if host plant quality is variable. In general, the present study contributes to our knowledge of anthropogenically unaltered processes affecting community assembly in a natural environment. The fundamental understanding of these processes is crucial for the identification of anthropogenic alterations and the establishment of sustainable management measures. The study points out the important role local factors can play for the distribution of organisms and thereby for community organisation. It emphasises the relevance of small scale heterogeneity of the abiotic and biotic environment to biodiversity and the need to consider these factors for development of effective conservation and restoration strategies.},
  subject      = {Savanne},
  language  = {en}
}
@phdthesis{Bertram2003,
  author    = {Bertram, Silke},
  title     = {Late Quaternary sand ramps in south-western Namibia - Nature, origin and palaeoclimatological significance},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6176},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Sand ramps have been (and still are) neglected in geomorphological research. Only recently any awareness of their potential of being a major source of palaeoenvironmental information, thanks to their multi-process character, has been developed. In Namibia, sand ramps were terra incognita. This study defines, classifies and systematizes sand ramps, investigates the formative processes and examines their palaeoenvironmental significance. The study region is located between the coastal Namib desert and the Great Escarpment, between the Tiras Mountains to the north and the Aus area to the south. Two lines of work were followed: geomorphological and sedimentological investigations in the field, assisted by interpretation of satellite images, aerial photographs and topographic maps, and palaeopedological and sedimentological analytical work in the laboratory. Two generations of sand ramps could be identified. The older generation, represented by a single sand ramp within the study region, is characterized by the presence of old basal sediments. The bulk of the sand ramps is assigned to the young generation, which is divided into three morpho-types: in windward positions voluminous ramps are found, in leeward positions low-volume ramps exist, either of very high or very low slope angle. The most distinct characteristic of sand ramp sediments is their formation by interacting aeolian deposition and fluvial slope wash. The last period of deposition, which shaped all the entire young sand ramps, but also the upper part of the old ramp, is suggested to have occurred after c. 40 ka BP, implying a highly dynamic climatic system during that time, with seasonal aridity and low-frequency, but high-intensity rainfall. A phase of environmental stability followed, most likely around 25 ka BP, supporting growth of vegetation, stabilization and consolidation of the sediments as well as soil formation. Subsequently, the profile was truncated and a desert pavement formed, under climatic conditions comparable to those of the present semi-desert. The ramps were then largely cut off from the bedrock slopes, implying a change towards higher ecosystem variability. As the final major process, recent and modern aeolian sands accumulated on the upper ramp slopes. A luminescence date for the recent sand places their deposition at about 16 ka BP, close to the Last Glacial Maximum. Regarding the source of the sands, a local origin is proposed. For the sand ramp of the old generation the "basic cycle" of initial deposition, stabilization and denudation occurred twelve times, including a phase of calcrete and/or root-cast formation in each of them, adding up to around 60 changes in morphodynamics altogether. At least nine of these cycles took place between 105 ka BP and the LGM, indicating that the general cooling trend during the Late Pleistocene was subject to a high number of oscillations of the environmental conditions not identified before for southern Namibia. Due to the high resolution obtained by the study of sand ramp sediments, but also due to the very special situation of the study area in a desert margin, 100 km from the South Atlantic and in the transition zone between summer and winter rainfall, correlation with stratigraphies (of mostly lower resolution) established for different regions in southern Africa did not appear promising. In conclusion, sand ramps generally serve as a valuable tool for detailed deciphering of past morphodynamics and thereby palaeoenvironmental conditions. For south-west Namibia, sand ramps shed some more light on the Late Quaternary landscape evolution.},
  subject      = {Namibia <S{\"u}dwest>},
  language  = {en}
}
@phdthesis{Krapf2003,
  author    = {Krapf, Carmen},
  title     = {Ephemeral river systems at the Skeleton Coast, NW-Namibia - Sedimentological and geomorphological studies on the braided river dominated Koigab Fan, the Cenozoic succession in the Uniabmond area and comparative studies on fluvio-aeolian interaction between ephemeral rivers and the Skeleton Coast Erg},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6013},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The Skeleton Coast forms part of the Atlantic coastline of NW Namibia comprising several ephemeral rivers, which flow west-southwest towards the Atlantic Ocean. The area is hyper-arid with less than 50 mm average annual rainfall and a rainfall variability of 72\%. Therefore, the major catchment areas of the rivers are about 100-200 km further inland in regions with relatively high annual rainfall of 300-600 mm. The coastal plain in the river downstream areas is characterized by a prominent NNW trending, 165 km long belt of 20-50 m high, locally compound, barchanoid and transverse dunes. This dune belt, termed Skeleton Coast Erg, starts abruptly with a series of barchans and large compound dunes 15 km north of the Koigab River and extends from 2-5 km inland sub-parallel to the South Atlantic margin of NW Namibia over a width of 3-20 km. As the SSE-NNW trending dune belt is oriented perpendicular to river flow, the dunefield dams and interacts with the west-southwestward flowing ephemeral river systems. This study focused on three main topics: 1) investigation and classification of the Koigab Fan, 2) the investigation of the Cenozoic succession in the Uniabmond area and 3) comparative studies of fluvio-aeolian interaction between five ephemeral rivers and the Skeleton Coast Erg. Sedimentological and geomorphological investigations show that the Koigab Fan represents a yet undocumented type of a braided fluvial fan system, which operates in an arid climatic, tropical latitude setting, is dominated by ephemeral mixed gravel/sand braided rivers, lacks significant vegetation on the fan surface, has been relatively little affected by human activity, is a perfect study site for recording various types of fluvio-aeolian interaction and thereby acts additionally as a model for certain Precambrian and Early Palaeozoic fan depositional systems deposited prior to the evolution of land plants. The Cenozoic succession in the Uniabmond area consists of three major unconformity-bounded units, which have been subdivided into the Red Canyon, the Whitecliff, and the Uniabmond Formation. The Tertiary Red Canyon Fm. is characterized by continental reddish sediments documenting an alluvial fan and braided river to floodplain depositional environment. The Whitecliff Fm. displays a wide variety of continental and marine facies. This formation provides the possibility to examine fluvio-aeolian interactions and spectacular, steep onlap relationships towards older sediments preserved in ancient seacliffs. The Whitecliff Fm. has been subdivided into four sedimentary cycles, which resulted from sea level changes during the Plio- to Middle Pleistocene. The following Uniabmond Fm. provides a unique insight into the depositional history of the NW Namibian coast during the Last Pleistocene glacial cycle. The formation has been subdivided into four units, which are separated by unconformities controlled by sea level changes. Unit 1 represents deposits of an Eemian palaeo-beach. The overlying Units 2-4 build up the sedimentary body of the Uniab Fan, again a braided river dominated fan, which is nowadays degraded and characterized by deeply incised valleys, deflation surfaces and aeolian landforms. The Uniabmond Fm. is overlain by the dunes of the Skeleton Coast Erg, whose development is related to the Last Glacial Maximum (LGM). The damming of river flow by aeolian landforms has been previously recognized as one of several principal types of fluvio-aeolian interaction. Five ephemeral rivers (from S to N: Koigab, Uniab, Hunkab, Hoanib, Hoarusib), which variously interact with the Skeleton Coast Erg, were chosen for the purpose of this study to consider the variability of parameters within these fluvio-aeolian systems and the resulting differences in the effectiveness of aeolian damming. The fluvio-aeolian interactions between the rivers and the dune field are controlled by the climate characteristics and the geology of the river catchment areas, the sediment load of the rivers, their depositional architecture, the longitudinal river profiles as well as the anatomy of the Skeleton Coast Erg. Resulting processes are 1) aeolian winnowing of fluvially derived sediments and sediment transfer into and deposition in the erg; 2) dune erosion during break-through resulting in hyperconcentrated flow and intra-erg mass flow deposits; 3) the development of extensive flood-reservoir basins caused by dune damming of the rivers during flood; 4) interdune flooding causing stacked mud-pond sequences; and 5) the termination of the erg by more frequent river floods.},
  subject      = {Namibia <Nordwest>},
  language  = {en}
}
@phdthesis{Visan2003,
  author    = {Visan, Ion Lucian},
  title     = {P0 specific T-cell repertoire in wild-type and P0 deficient mice},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5734},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Zusammenfassung Das Myelinprotein P0 stellt eine zentrale Komponente f{\"u}r die Stabilit{\"a}t und Funktionalit{\"a}t der Myelinscheiden des peripheren Nervensystems dar. Mutationen des P0-Proteins f{\"u}hren zu verschiedenen, schwer behindernden peripheren Neuropathien wie der Charcot-Marie-Tooth- oder der Dejerine-Sotas-Erkrankung. Wir haben das Tiermodell der P0-Knock-Out-M{\"a}use verwendet, um im Vergleich zu den C57BL/6-Wildtyp-Tieren Selektionsmechanismen des P0-spezifischen T-Zell-Repertoires zu untersuchen. Dazu wurde eine Reihe von {\"u}berlappenden 20-mer-Peptiden benutzt, die die gesamte Aminos{\"a}uresequenz von P0 abdeckten. Mit Hilfe dieser Peptide wurde ein sog. „Epitop-Mapping" der H2-Ab-restringierten T-Zell-Antwort durchgef{\"u}hrt. Auf diese Weise konnte das P0-Peptid 5 (Aminos{\"a}ure 41-60) in der extrazellul{\"a}ren P0-Dom{\"a}ne als immunogene Determinante identifiziert werden. Dieses immunogene Peptid wurde dann f{\"u}r Untersuchungen der Toleranzmechanismen verwendet und zeigte, dass in P0-Knock-Out-M{\"a}usen ein hochreaktives P0-spezifisches T-Zell-Repertoire vorliegt, w{\"a}hrend es in Wildtyp-Tieren inaktiviert ist und so Selbsttoleranz erzeugt wird. Die Toleranzerzeugung in Wildtyp- und heterozygoten P0 +/- M{\"a}usen h{\"a}ngt nicht von der Gen-Dosis ab. P0 ist ein gewebespezifisches Antigen, dessen Expression normalerweise auf myelinisierende Schwann-Zellen beschr{\"a}nkt ist. Die klassischen Vorstellungen zu Toleranzmechanismen gegen{\"u}ber gewebsspezifischen Antigenen schrieben diese vor allem peripheren Immunmechanismen zu. Durch den erstmaligen Nachweis von intrathymischer Expression gewebsspezifischer Antigene wie P0 konnten wir best{\"a}tigen, dass f{\"u}r P0 offensichtlich die Expression deutlich weiter verbreitet ist, insbesondere auch auf Thymus-Stroma-Zellen. Unter Verwendung von Knochenmarkschim{\"a}ren haben wir weitere Untersuchungen durchgef{\"u}hrt, wie Knochenmarks-abstammende Zellen im Vergleich zu nicht-h{\"a}matopoetischen Zellen Toleranz gegen{\"u}ber P0 erzeugen k{\"o}nnen. Unsere Befunde zeigen, dass Knochenmarks-abh{\"a}ngige Zellen nicht ausreichen, um v{\"o}llige Toleranz zu erzeugen. Zus{\"a}tzlich wurde eine P0-Expression auf anderen Geweben wie dem Thymus ben{\"o}tigt, um komplette Toleranz zu erhalten. Wir identifizierten ein kryptisches P0-Peptid 8 und zwei subdominante P0-Peptide 1 und 3. W{\"a}hrend das Peptid 8 sowohl in Wildtyp- als auch Knock-Out-M{\"a}usen erkannt wurde, wurden die Peptide 1 und 3 in Wildtyp-M{\"a}usen nicht als Immunogen erkannt. Die genannten Peptide wurden verwendet, um eine experimentelle autoimmune Neuritis (EAN) zu erzeugen. Mit keinem der experimentellen Ans{\"a}tze konnten wir klinische Zeichen einer EAN generieren, allerdings mit dem Peptid 3 doch Entz{\"u}ndung im peripheren Nerven beobachten. Es werden zuk{\"u}nftig weitere Untersuchungen ben{\"o}tigt, um P0-spezifische T-Zell-Linien zu etablieren und so mit h{\"o}herer Effizienz eine EAN zu erzeugen. Unsere Untersuchungen sprechen daf{\"u}r, dass bei gentherapeutischen Ans{\"a}tzen bei erblichen Neuropathien vorsichtig und schrittweise vorgegangen werden muss, da mit sekund{\"a}rer Autoimmunit{\"a}t und damit Inflammation im peripheren Nerven zu rechnen ist.},
  subject      = {Myelin},
  language  = {en}
}
@phdthesis{Kraemer2003,
  author    = {Kr{\"a}mer, Franziska},
  title     = {Molecular and Biochemical Investigations into VMD2, the gene associated with Best Disease},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5761},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Best disease (OMIM 153700) is an early-onset, autosomal dominant maculopathy characterized by egg yolk-like lesions in the central retina. The disease gene, the vitelliform macular dystrophy gene type 2 (VMD2), encodes a 585-aa VMD2 transmembrane protein, termed bestrophin. The protein is predominantly expressed on the basolateral side of the retinal pigment epithelium (RPE) and is thought to be involved in the transport of chloride ions. Bestrophin as well as three closely related VMD2-like proteins (VMD2L1-L3) contain multiple putative transmembrane (TM) domains and an invariant tripeptide (RFP) motif in the N-terminal half of the protein. This and the tissue-restricted expression to polarized epithelial cells are typical features of the VMD2 RFP-TM family. Best disease is predominantly caused by missense mutations, clustering in four distinct „hotspots" in the evolutionary highly conserved N-terminal region of the protein. To further augment the spectrum of mutations and to gain novel insights into the underlying molecular mechanisms, we screened VMD2 in a large cohort of affected patients. In total, nine novel VMD2 mutations were identified, raising the total number of known Best disease-related mutations from 83 to 92. Eight out of nine novel mutations are hotspot-specific missense mutations, underscoring their functional/structural significance and corroborating the dominant-negative nature of the mutations. Of special interest is a one-basepair deletion (Pro260fsX288) encoding a truncated protein with a deletion of an important functional domain (TM domain four) as well as the entire C-terminal half of bestrophin. For the first time, a nonsense mutation leading to a 50 \% non-functional protein has been identified suggesting that on rare occassions Best disease may be caused by haploinsufficiency. Molecular diagnostics strongly requires a reliable classification of VMD2 sequence changes into pathogenic and non-pathogenic types. Since the molecular pathomechanism is unclear at present, the pathogenicity of novel sequence changes of VMD2 are currently assessed in light of known mutations. We therefore initiated a publicly accessible VMD2 mutation database (http://www.uni-wuerzburg.de/humangenetics/vmd2.html) and are collecting and administrating the growing number of mutations, rare sequence variants and common polymorphisms. Missense mutations may disrupt the function of proteins in numerous ways. To evaluate the functional consequences of VMD2 mutations in respect to intracellular mislocalization and/or protein elimination, a set of molecular tools were generated. These included the establishment of an in vitro COS7 heterologous expression assay, the generation of numerous VMD2 mutations by site-directed mutagenesis as well as the development of bestrophin-specific antibodies. Surprisingly, membrane fractionation/Western blot experiments revealed no significant quantitative differences between intact and mutant bestrophin. Irrelevant of the type or location of mutation, incorporation of mutant bestrophin to the membraneous fraction was observed. Thus, impaired membrane integration may be ruled out as causative pathomechanism of Best disease consistent with a dominant-negative effect of the mutations. In a different approach, efforts were directed towards identifying and characterizing the VMD2 RFP-TM protein family in mouse. While clarification of the genomic organization of murine Vmd2 was required as basis to generate Vmd2-targeted animals (see below), the study of closely related proteins (Vmd2L1, Vmd2L2 and Vmd2L3) may provide further clues as to the function of bestrophin. For this, biocomputational as well as RT PCR analyses were performed. Moreover, the novel genes were analyzed by real time quantitative RT PCR, displaying predominant expression in testis, colon and skeletal muscle of Vmd2, Vmd2L1 and Vmd2L3 transcripts, respectively as well as in eye tissue. Interestingly, neither an ORF was determined for murine Vmd2L2 nor was the transcript present in a panel of 12 mouse tissues, suggesting that murine Vmd2L2 may represent a functionally inactive pseudogene. The murine Vmd2L3 gene, as its human counterpart, is a highly differentially spliced transcript. Finally, generating mouse models of Best disease will provide essential tools to investigate the pathophysiology of bestrophin in vivo. We have initiated the generation of two different mouse lineages, one deficient of Vmd2 (knock-out) and the other carrying a human disease-related mutation (Tyr227Asn) in the orthologous murine gene (knock-in). Genetic engineering of both constructs has been achieved and presently, four ES clones harboring the homologous recombination event (Vmd2+/-) have been isolated and are ready for the subsequent steps to generate chimeric animals. The resulting mouse lineages will represent two key models to elucidate the functional role of bestrophin in Best disease, in RPE development and physiology.},
  subject      = {Best-Krankheit},
  language  = {en}
}
@phdthesis{Herold2003,
  author    = {Herold, Andrea},
  title     = {The role of human and Drosophila NXF proteins in nuclear mRNA export},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5601},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {A distinguishing feature of eukaryotic cells is the spatial separation of the site of mRNA synthesis (nucleus) from the site of mRNA function (cytoplasm) by the nuclear envelope. As a consequence, mRNAs need to be actively exported from the nucleus to the cytoplasm. At the time when this study was initiated, both human TAP and yeast Mex67p had been proposed to play a role in this process. Work presented in this thesis (section 2.1) revealed that TAP and Mex67p belong to an evolutionarily conserved family of proteins which are characterized by a conserved modular domain organization. This family was termed nuclear export factor (NXF) family. While the yeast genome encodes only one NXF protein (Mex67p), the genomes of higher eukaryotes encode several NXF proteins. There are two nxf genes in C. elegans and A. gambiae, four in D. melanogaster, and at least four in H. sapiens and M. musculus. It was unclear whether, apart from TAP and Mex67p, other members of this family would also be involved in mRNA export. In the first part of this thesis (2.1), several human NXF members were tested for a possible function in nuclear mRNA export. They were analyzed for their interaction with RNA, nucleoporins and other known TAP partners in vitro, and tested for their ability to promote nuclear export of a reporter mRNA in vivo. Using these assays, human NXF2, NXF3 and NXF5 were all shown to interact with the known NXF partner p15. NXF2 and NXF5 were also found to bind directly to RNA, but only NXF2 was able to bind directly to nucleoporins and to promote the nuclear export of an (untethered) reporter mRNA. Thus NXF2 possesses many and NXF3 and NXF5 possess some of the features required to serve as an export receptor for cellular mRNAs. As NXF2 and NXF3 transcripts were mainly found in testis, and the closest orthologue of NXF5 in mouse has the highest levels of expression in brain, these NXF members could potentially serve as tissue-specific mRNA export receptors. In the second part of this work (2.2), the role of different Drosophila NXF proteins and other export factors in mRNA export was investigated using double-stranded RNA interference (RNAi) in Drosophila Schneider cells. Three of the four predicted Drosophila NXF members (NXF1-3) were found to be expressed in this cell line and could be targeted by RNAi. Depletion of endogenous NXF1 inhibited growth and resulted in the nuclear accumulation of polyadenylated RNA. Fluorescence in situ hybridization revealed that export of both heat shock and non-heat shock mRNAs, including intron-containing and intronless mRNAs, was inhibited. Depleting endogenous NXF2 or NXF3 had no apparent phenotype. These results suggested that NXF1 (but not NXF2-NXF4) mediates the export of bulk mRNA in Drosophila cells. We and others have shown that human NXF proteins function as heterodimers bound to the small protein p15. Accordingly, silencing of Drosophila p15 resulted in a block of mRNA export which was indistinguishable from the export inhibition seen after targeting NXF1. These observations indicated that neither NXF1 nor p15 can promote export in the absence of the other subunit of the heterodimer. NXF1:p15 heterodimers are implicated in late steps of mRNA export, i.e. in the translocation of mRNP export cargoes across the nuclear pore complex. The mechanism by which NXF1:p15 dimers are recruited to the mRNA is unclear. A protein that is thought to play a role in this process is the putative RNA helicase UAP56. Similar to NXF1 and p15, UAP56 was shown to be essential for mRNA export in Drosophila. UAP56 is recruited cotranscriptionally to nascent transcripts and was suggested to facilitate the interaction of NXF1:p15 with mRNPs. Even though both NXF1:p15 heterodimers and UAP56 had been implicated in general mRNA export, it was unclear whether there are classes of mRNAs that require NXF1:p15, but not UAP56 or vice versa. It was also unclear what fraction of cellular mRNAs is exported by NXF1:p15 dimers and UAP56, and whether mRNAs exist that reach the cytoplasm through alternative routes, i.e. by recruiting other export receptors. To address these issues we performed a genome-wide analysis of nuclear mRNA export pathways using microarray technology (2.2.2). We analyzed the relative abundance of nearly half of the Drosophila transcriptome in the cytoplasm of Drosophila Schneider cells depleted of different export factors by RNAi. We showed that the vast majority of transcripts were underrepresented in the cytoplasm of cells depleted of NXF1, p15 or UAP56 as compared to control cells. Only a small number of mRNAs were apparently not affected by the depletions. These observations, together with the wide and similar effects on mRNA levels caused by the depletion of NXF1, p15 or UAP56, indicate that these proteins define the major mRNA export pathway in these cells. We also identified a small subset of mRNAs which appeared to be exported by NXF1:p15 dimers independently of UAP56. In contrast, no significant changes in mRNA expression profiles were observed in cells depleted of NXF2 or NXF3, suggesting that neither NXF2 nor NXF3 play an essential role in mRNA export in Drosophila Schneider cells. Crm1 is a transport receptor implicated in the export of a variety of non-mRNA and protein cargoes. In addition, human Crm1 has been suggested to be involved in the export of a specific mRNA species, serving as a "specialized" mRNA export receptor. A role of human Crm1 in the export of bulk mRNA is considered unlikely. We analyzed the role of Drosophila Crm1 in mRNA export by inhibiting Crm1 with the drug leptomycin B in Schneider cells. Subsequent microarray analysis demonstrated that the inactivation of Crm1 resulted in decreased cytoplasmic levels of less than 1\% of all mRNAs, indicating that Crm1 is indeed not a major mRNA export receptor. The genome-wide analysis also revealed a feedback loop by which a block to mRNA export triggers the upregulation of genes involved in this process. This thesis also includes two sections describing projects in which I participated during my Ph.D., but which were not the main focus of this thesis. In section 2.3, the role of the different TAP/NXF1 domains in nuclear mRNA export is discussed. Section 2.4 describes results that were obtained as part of a collaboration using the RNAi technique in Schneider cells to study the function of Cdc37.},
  subject      = {Zellkern},
  language  = {en}
}
@phdthesis{Tsai2003,
  author    = {Tsai, Chyn-Bey},
  title     = {Molecular cloning and characterization of nitrate reductase from Ricinus communis L. heterologously expressed in Pichia pastoris},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5544},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Zusammenfassung Hintergrund: In einer vorhergehenden Studie wurde gezeigt, dass die Nitratreduktase (NR, EC 1.6.6.1) aus Bl{\"a}ttern von Ricinus communis L. im Vergleich zu NRs der meisten anderen h{\"o}heren Pflanzen durch verschiedene Faktoren unterschiedlich reguliert wird. Die Aktivit{\"a}t ist ungew{\"o}hnlich Mg2+-sensitiv, zeigt ein ver{\"a}ndertes pH-Profil und ist nur gering ATP-abh{\"a}ngig inaktivierbar. Das Ziel dieser Arbeit war, die abweichenden Eigenschaften von Ricinus NR, aus molekularer und physiologischer Sicht detaillierter aufzukl{\"a}ren. Zu diesem Zweck wurde das NR Gen von R. communis geklont, heterolog exprimiert und charakterisiert. Ergebnisse: Die abgeleitete Proteinsequenz zeigte, dass Ricinus NR hohe {\"A}hnlichkeit mit anderem NRs teilte, abgesehen von der N-terminalen Region. In der N-terminalen Region besitzt die Ricinus NR eine s{\"a}urehaltige Sequenz, die nur in den h{\"o}heren Pflanzen konserviert ist. In der Moco-bindenden Region waren einige in 17 Pflanzen NRs konservierte Aminos{\"a}urepositionen ver{\"a}ndert. Zu diesen Positionen geh{\"o}rten His103, Gln123, Val266 und Ala284, die Asparagin, Arginin, Aspartat und Prolin in den anderen Pflanzen ersetzten. Auch an der Dimerisierungs- und Hinge 1-Region, zeigte die Ricinus NR eine ver{\"a}nderte Aminos{\"a}uresequenz. Anstatt Isoleucin und Glycin, besaß die Ricinus NR an den Stellen 460 und 498 Asparagin und Alanin. Durch ein Arg an der Stelle 482 kommt es zu einer zus{\"a}tzliche Trypsinschnittstelle innerhalb des 481KRHK484-Motivs (die meisten NR besitzen hier KPHK). Zus{\"a}tzlich enth{\"a}lt die Ricinus NR eine Serinphosphorylierungsstelle (Ser-526) innerhalb des m{\"o}glichen 14-3-3 Bindemotivs 523KSVS*TP528, was eine allgemeine Eigenschaft von Nitratreduktasen ist. Im C-Terminus von Ricinus NR best{\"a}tigte die Sequenz 886CGPPP890, dass die Ricinus NR ein NADH-spezifisches Enzym ist. Die Ricinus NR und Arabidopsis NR2 (AtNR2) wurden in Pichia pastoris funktionell exprimiert und die Eigenschaften miteinander verglichen. Die rekombinante Ricinus NR (RcNR) selbst wurde nicht durch die Inkubation mit MgATP inhibiert, ebenso AtNR2. Da der Hefeextrakt vermutlich die Faktoren zur Regulierung der NR nicht enth{\"a}lt, wurden entsalzte Blattextrakte von Arabidopsis (ADL), Spinat (SDL) und Ricinus (RDL) zugesetzt, die Kinasen und 14-3-3 Proteine enthielten. Damit keine endogenen NRs sich im Extrakt befinden wurden die Bl{\"a}tter vor Extraktion 4 Tage im Dunkeln gehalten. In Bezug auf die Inhibierung der NR durch ATP wurde festgestellt, dass die RcNR gegen{\"u}ber einer solchen Inhibierung unempfindlich ist, AtNR2 dagegen in jedem Fall durch ATP inaktiviert wird. Bei Kombination von RcNR mit NR-freien Extrakten aus Pflanzen zeigte sich die erh{\"o}hte Mg2+-Sensitivit{\"a}t nur, wenn man RcNR mit RDL inkubierte, nicht aber wenn man RcNR mit SDL oder ADL inkubierte. Es liegt auf der Hand, dass ein oder einige Faktoren in RDL vorkommen, die mit RcNR interagieren und seine hohe Mg2+-Sensitivit{\"a}t hervorrufen. Außerdem, ergab eine Inkubation von AtNR2 mit unterschiedlichen NR-freien Blattextrakten eine bedeutende Aktivierung der Enzymaktivit{\"a}ten, sowohl in Anwesenheit von Mg2+ als auch EDTA. Dies wurde jedoch nicht f{\"u}r die RcNR festgestellt. Nach Verwendung von Ammoniumsulfat zur Fraktionierung des RDL, fand man zus{\"a}tzlich heraus, dass ungef{\"a}hr 0,2 mg des Proteins der Fraktion die mit 0-35\% Ammoniumsulfat gef{\"a}llt wurde ausreichten die maximale Hemmung des RcNR hervorzurufen. Schlussfolgerungen: Die Unempfindlichkeit gegen{\"u}ber ATP erscheint eine angeborene Eigenschaft von Ricinus NR, w{\"a}hrend die hohe Mg2+-Sensitivit{\"a}t von einem oder einigen Faktoren in den Bl{\"a}ttern von Ricinus abh{\"a}ngt. Diese(r) bis jetzt unbekannte Faktor(en) war Hitze-sensitiv und konnte durch Ammoniumsulfat ausgef{\"a}llt werden. Er scheint spezifisch auf die rekombinante Ricinus-NR einzuwirken, und liefert eine Mg2+-Sensitivit{\"a}t vergleichbar dem authentischen Blattenzym. Außerdem gibt es vermutlich auch positiv regulierende Faktor(en) f{\"u}r die Nitratreduktase aus Bl{\"a}ttern h{\"o}herer Pflanzen.},
  subject      = {Rizinus},
  language  = {en}
}
@phdthesis{Hofmann2003,
  author    = {Hofmann, Markus},
  title     = {Signal transduction during defense response and source-sink transition in tomato},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5421},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Plants have evolved an elaborate system to cope with a variety of biotic and abiotic stresses. Typically, under stress conditions an appropriate defense response is invoked which is accompanied by changes in the metabolic status of the plant. Photosynthesis is downregulated and sucrose is imported into the tissue, which provides a faster and more constant flux of energy and carbon skeletons to perform the defense response. Interestingly, these processes are co-ordinately regulated and the signal transduction chains underlying these cellular programs appear to share at least some common elements. Both the induction of sink metabolism and defense response is dependent on signal transduction pathways involving protein phosphorylation. Furthermore, regulation of extracellular invertase (INV) and phenylalanine ammonia lyase (PAL) which are markers for sink metabolism and defense response is preceded by the transient activation of MAP kinases. In depth analysis of MAP kinase activation by partial purification led to the discovery that, depending on the stimulus, different subsets of MAP kinases are activated. This differential MAPK activation is likely to possess a signal encoding function. In addition, the partial purification of MAP kinases was found to be suitable to address specific cellular functions to individual MAP kinase isoenzymes. By this way, LpWIPK was identified as the major MAP kinase activity induced after stimulation of tomato cells with different elicitors. LpWIPK is thus considered as a key regulator of defense response together with sink induction in tomato. A study using nonmetabolisable sucrose analogs revealed that the regulation of photosynthesis is not directly coupled to this signal transduction pathway since it is independent of MAP kinase activation. Nonetheless, downregulation is induced by the same stimuli that induce the defense response and sink metabolism and it will therefore be interesting to uncover the branch points of this signalling network in the future. MAP kinases are not only central components regulating the response to biotic stresses. In addition to e.g. pathogens, MAP kinases are as well involved in signal transduction events invoked by abiotic stresses like cold and drought. In a recent study, we could show that a MAP kinase is activated by heat stress, under conditions a plant will encounter in nature. This previously unknown MAP kinase is able to specifically recognise the heat stress transcription factor HsfA3 as a substrate, which supports a role of this MAP kinase in the regulation of the heat stress response. Moreover, the observation that HsfA3 is phosphorylated by the heat activated MAP kinase in vitro provides a promising basis to identify HsfA3 as the first physiological substrate of a plant MAP kinase. Intracellular protons have been implicated in the signal transduction of defense related signals. In a study using Chenopodium rubrum cells, we could show that cytosolic changes in pH values do not precede the regulation of the marker genes INV and PAL. Depending on the stimulus applied, cytosolic acidification or alkalinisation can be observed, which excludes a role for protons as signals in this pathway. Together with the concomitant changes of the pH value of the extracellular space, these variations can thus be considered as terminal part of the defense response itself rather than as a second messenger. WRKY transcription factors have only recently been identified as indirect targets of a central plant MAP kinase cascade. In addition, the identification of cognate binding sites in the promoters of INV and PAL supports a role for these proteins in the co-ordinate regulation of defense response and sink induction. A novel elicitor responsive WRKY transcription factor, LpWRKY1, was cloned from tomato and characterised with respect to its posttranslational modification. This immediate early transcription factor is transiently induced upon pathogen attack and the induction is dependent on phosphorylation. Furthermore, it was shown for the first time with respect to WRKY transcription factors, that LpWRKY1 is phosphorylated in vivo. Analysis of the role of this phosphorylation by in gel assays using recombinant WRKY protein as the substrate revealed two protein kinases that are transiently activated during the defense response to phosphorylate LpWRKY1. This data demonstrates that WRKY proteins require phosphorylation to modulate their DNA binding or transactivating activity.},
  language  = {en}
}
@phdthesis{Visan2003,
  author    = {Visan, Ioana Andreea},
  title     = {The CD23 receptor-regulation of expression and signal transduction},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5556},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Bisher sind zwei Isoformen des humanen CD23 (CD23a und CD23b) beschrieben. Beide unterscheiden sich lediglich in 6-7 Resten im N-terminalen, zytoplasmatischen Anteil. CD23a wird ausschließlich auf B-Zellen exprimiert, w{\"a}hrend CD23b sowohl auf B-Zellen als auch auf Monozyten, eosinophilen Granulozyten, Makrophagen und zahlreichen anderen Zelltypen durch Stimulation mit IL-4 induziert werden kann. Die beiden Isoformen vermitteln wahrscheinlich unterschiedliche Funktionen. CD23a gilt als Isoform, welche vornehmlich mit der Endozytose von IgE-Immunkomplexen und der Vermittlung von Antigen-Pr{\"a}sentation auf B-Zellen assoziiert ist. CD23b besitzt ein Phagozytose-Motiv und scheint bei der Phagozytose IgE besetzter Partikel, der Freisetzung von Zytokinen und der Bildung von Peroxiden eine Rolle zu spielen. Fr{\"u}here Untersuchungen legen die Vermutung nahe, dass die beiden Isoformen zwei getrennte Signal{\"u}bertragungswege miteinander verbinden. Die Gegen{\"u}berstellung von Ereignissen, welche in Zellen, die nur eine einer oder beide Isoformen von CD23 besitzen, stattfinden, legt die Vermutung nahe, dass CD23b cAMP und iNOS hochreguliert, wohingegen CD23a einen Anstieg des intrazellul{\"a}ren Kalziums vermittelt. Im ersten Teil unserer Untersuchungen haben wir die Regulation der B-Zell-spezifischen Expression von CD23a analysiert. Pax-5 ist ein auf B-Zellen beschr{\"a}nkter Transkriptionsfaktor, welcher f{\"u}r die fr{\"u}he und sp{\"a}te B-Zellentwicklung von entscheidender Bedeutung ist. M{\"o}gliche Pax-5 Bindungsstellen wurden in den proximalen Abschnitten des CD23a Promotors vermutet. Die Analyse des CD23a Promotors ergab drei mutmaßliche Pax-5 Bindungsstellen mit mehr als 50\% Homologie zur Konsensus-Sequenz. Eine dieser Bindungsstellen, namens CD23-1, kann mit einer hochaffinen Pax-5 Bindungsstelle konkurrieren oder direkt das Pax-5 Protein in Elektromobilit{\"a}ts Experimenten (EMSA) binden. Das Einf{\"u}gen von Mutationen an dieser Stelle verhindert die Bindung. Ein weiterer Versuch, bei dem die gesamte L{\"a}nge des CD23a Promotors durch {\"u}berlappende Peptide in einem kompetitiven Verfahren gegen{\"u}ber hoch affinen Bindungsstellen getestet wurde, zeigt ebenso CD23-1 als die einzige Stelle, welche direkt Pax-5 binden kann. In weiteren Experimenten f{\"u}hrte die Expression von Pax-5 in 293 Zellen zu einer 7fachen Aktivierung eines CD23a Kernpromotor Konstrukts. Die Kotransfektion zusammen mit STAT6 zeigte, dass Pax-5 mit diesem Transkriptionsfaktor kooperiert, indem es die Transkriptionsrate eines vergr{\"o}ßerten CD23a Promotorkonstrukts erh{\"o}ht. Von besonderer Bedeutung ist die Tatsache, dass die ektope Expression von Pax-5 in der monozyt{\"a}ren Zelllinie U-937, die normalerweise nur die CD23b Isoform exprimiert, dann zu einer Expression von CD23a nach Stimulation mit IL-4 und PMA f{\"u}hrte. Unsere Ergebnisse legen nahe, dass Pax-5 in der auf B-Zellen beschr{\"a}nkten Expression der CD23 Isoform eine Schl{\"u}sselrolle zukommt. Im zweiten Teil des Projekts haben wir ein "Zwei-Hefen-Hybrid-System" (Cyto-Trap von Stratagene) verwendet, um nach zytoplasmatischen Interaktionspartnern f{\"u}r den CD23 Rezeptor zu suchen. Das System wurde modifiziert um eine hohe Effizienz an Transformation zu erzielen. Unterschiedliche „K{\"o}der"-Vektorkonstrukte wurden hergestellt. Das Screening wurde mittels einer humanen Milzbibliothek mit dem Zielvektor des Systems durchgef{\"u}hrt. Die anfangs benutzten Konstrukte -pSosCD23a und pSosCD23b - exprimierten sehr kurze (22 Aminos{\"a}uren) zytoplasmatischen Reste der Isoformen am C-terminalen Ende des Fusionsproteins (humanes SOS). Verbesserte Konstrukte (pSos CD23a+Linker und pSosCD23b+Linker) exprimierten den zytoplasmatischen Anteil von CD23a/b am N-terminalen Ende des humanen SOS und hatten folglich den N-terminalen Anteil als Andockstelle frei, entsprechend den Bedingungen in vivo. Eine flexible Verbindungsregion trennte die Fusionsproteine, um auf diese Weise die kurze Aminos{\"a}urekette deutlich „sichtbar" werden zu lassen. Ann{\"a}hernd drei Millionen Klone wurden mittels der verschiedenen Konstrukte untersucht. Dabei konnte keine tats{\"a}chlich positive Interaktion gefunden werden. Stattdessen fand sich eine vergleichsweise hohe Zahl falsch-positiver Klone. Diese wiederum wurden in einem zweiten "Zwei-Hefen-Hybrid-System" getestet. In Zukunft wird ein neues Konstrukt als K{\"o}der verwendet werden. Hierbei wurde ein Tyrosin-Rest im zytoplasmatischen Anteil von CD23a durch Glutamat ersetzt. Das System wurde bereits dazu verwendet, die Interaktion zwischen CD23 und p59fyn - einem Mitglied der Src-Familie von Proteinkinasen, welches mit CD23a assoziiert sein soll - zu testen. Jedoch konnte im CytoTrap "Zwei-Hefen-Hybrid-System" keine Wechselwirkung nachgewiesen werden. Zusammenfassend zeigt das zentrale Ergebnis der Arbeit, dass Pax-5 der Schl{\"u}sselregulator ist, der die B-Zell-spezifische Expression von CD23a erm{\"o}glicht. Zus{\"a}tzlich wurde ein "Zwei-Hefen-Hybrid-System" etabliert, mit dem zytoplasmatische Interaktionspartner f{\"u}r die CD23 Isoformen gefunden werden k{\"o}nnen.},
  subject      = {Antigen CD23},
  language  = {en}
}
@phdthesis{Jha2003,
  author    = {Jha, Mithilesh Kumar},
  title     = {Protein Kinase A regulates GATA-3 dependent Activation of IL-5 Gene Expression in T Helper Lymphocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5281},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Die durch Agentien wie IL-1\&\#945;, Prostaglandine oder Forskolin induzierte Erh{\"o}hung von intrazellul{\"a}rem zyklischem Adenosin-Monophosphat (cAMP) in T-Lymphozyten inhibiert die Synthese Th1-typischer Zytokine und stimuliert die Synthese Th2-typischer Zytokine. Die f{\"u}r die cAMP-vermittelte Induktion von Th2-Zytokinen verantwortlichen Signaltransduktionskaskaden sind bisher nur unvollst{\"a}ndig aufgekl{\"a}rt. Deshalb konzentrierte sich meine Dissertation auf die Erforschung des cAMP-Signalweges in prim{\"a}ren T-Helferzellen. W{\"a}hrend die Induktion muriner EL-4 T-Zellen mit Forskolin sowohl zur Aktivierung Th2-typischer als auch zur Inhibierung Th1-typischer Lymphokine f{\"u}hrt, kann die ektopische Expression einer katalytisch aktiven Proteinkinase A (PKA) zwar die Synthese von Th2-typischen Lymphokinen stimulieren, nicht jeder die Expression Th1-typischer Lymphokine inhibieren. Dies bedeutet, dass die Aktivierung von PKA selektiv an der Stimulation der Th2-Lymphokinexpression beteiligt ist, w{\"a}hrend andere, cAMP-abh{\"a}ngige Signaltransduktionswege zur Inhibierung Th1-typischer Lymphokine f{\"u}hren. Durch vergleichende Analysen verschiedener Th-Zellen konnte im Rahmen dieser Arbeit gezeigt werden, dass durch aktive PKA in Th0- und Th2, nicht jeder in Th1-Zellen die Expression von IL-5 erh{\"o}ht wird. Dieses Ph{\"a}nomen ist wahrscheinlich auf die unterschiedliche Konzentration des Transkriptionsfaktors GATA-3 zur{\"u}ckzuf{\"u}hren. So kommt GATA-3 in Th2-Zellen in hoher, in Th0-Zellen in geringerer und in Th1-Zellen in sehr geringer Konzentration vor. Die ektopische Expression von GATA-3 in Th1-Zellen induziert die Synthese Th2- typischer Lymphokine, die durch erh{\"o}hte cAMP-Konzentration oder durch aktive PKA noch verst{\"a}rkt werden kann. Untersuchungen bez{\"u}glich des Einflusses erh{\"o}hter cAMP-Spiegel auf Th2- Lymphokine in der Th2-Zelllinie D10 zeigten, dass erh{\"o}hte cAMP-Konzentrationen nicht die PKA-Aktivit{\"a}t, sondern vielmehr die Aktivit{\"a}t der p38-Kinase stimuliert. Diese Aktivierung f{\"u}hrt zur Phosphorylierung von GATA-3 und dadurch zur Induktion der IL-5- und IL-13-Expression (Chen et al., 2000). In prim{\"a}ren T-Helferzellen, die im Mittelpunkt der hier vorgelegten Arbeit standen, konnte beobachtet werden, dass bereits die Expression der katalytischen Untereinheit \&\#945; der PKA ausreichend f{\"u}r eine optimale IL-5-Expression in Th0-Zellen ist. Die Beobachtung, dass prim{\"a}re Th2-Zellen sowohl auf die Behandlung mit dem spezifischen PKA-Inhibitor H-89 als auch auf die ektopische Expression der negativ wirkenden Untereinheit 1 der PKA mit signifikant verminderter IL-5-Produktion reagierten, unterstreicht die wichtige Rolle aktiver PKA bei der Regulation des IL-5 Gens. Zusammenfassend konnte in dieser Arbeit durch die Untersuchung verschiedener prim{\"a}rer CD4+ T-Lymphozyten, einschließlich der auch in vivo IL-5 produzierenden Th2-Zellen, gezeigt werden, dass der Adenylzyklase/cAMP/PKASignaltransduktionsweg bedeutend f{\"u}r die IL-5 Genexpression in prim{\"a}ren Th2-Zellen und somit auch wichtig f{\"u}r deren Effektorfunktion ist.},
  language  = {en}
}
@phdthesis{Schwaerzel2003,
  author    = {Schw{\"a}rzel, Martin},
  title     = {Localizing engrams of olfactory memories in Drosophila},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5065},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Zars and co-workers were able to localize an engram of aversive olfactory memory to the mushroom bodies of Drosophila (Zars et al., 2000). In this thesis, I followed up on this finding in two ways. Inspired by Zars et al. (2000), I first focused on the whether it would also be possible to localize memory extinction.While memory extinction is well established behaviorally, little is known about the underlying circuitry and molecular mechanisms. In extension to the findings by Zars et al (2000), I show that aversive olfactory memories remain localized to a subset of mushroom body Kenyon cells for up to 3 hours. Extinction localizes to the same set of Kenyon cells. This common localization suggests a model in which unreinforced presentations of a previously learned odorant intracellularly antagonizes the signaling cascades underlying memory formation. The second part also targets memory localization, but addresses appetitive memory. I show that memories for the same olfactory cue can be established through either sugar or electric shock reinforcement. Importantly, these memories localize to the same set of neurons within the mushroom body. Thus, the question becomes apparent how the same signal can be associated with different events. It is shown that two different monoamines are specificaly necessary for formation of either of these memories, dopamine in case of electric shock and octopamine in case of sugar memory, respectively. Taking the representation of the olfactory cue within the mushroom bodies into account, the data suggest that the two memory traces are located in the same Kenyon cells, but in separate subcellular domains, one modulated by dopamine, the other by octopamine. Taken together, this study takes two further steps in the search for the engram. (1) The result that in Drosophila olfactory learning several memories are organized within the same set of Kenyon cells is in contrast to the pessimism expressed by Lashley that is might not be possible to localize an engram. (2) Beyond localization, a possibible mechanism how several engrams about the same stimulus can be localized within the same neurons might be suggested by the models of subcellular organisation, as postulated in case of appetitive and aversive memory on the one hand and acquisition and extinction of aversive memory on the other hand.},
  subject      = {Taufliege},
  language  = {en}
}
@phdthesis{Hassouneh2003,
  author    = {Hassouneh, Mohammed H.},
  title     = {Interpretation of Potential Fields by Modern Data Processing and 3-dimensional gravity Modeling of the Dead Sea Pull-Apart Basin / Jordan Rift Valley (JRV)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-4834},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {This work presents the analysis, 3D modeling and interpretation of gravity and aeromagnetic data of Jordan and Middle East. The potential field data delineate the location of the major faults, basins, swells, anticlines, synclines and domes in Jordan. The surface geology of Jordan and the immediate area east of the Rift is dominated by two large basins, the Al-Jafr basin in the south and the Al-Azraq-Wadi as Sirhan basin to the northeast. These two basins strike southeast-northwest and are separated by an anticlinal axis, the Kilwah-Bayir swell. The Karak Wadi El Fayha fault system occurs along the western flank of the swell. The Swaqa fault occurs on the southwest hinge of Al-Azraq basin and the Fuluq fault occurs on its northeast hinge. In the south west of Jordan, Wadi Utm-Quwaira and Disi-Mudawara fault zones are shown clearly in the aeromagnetic and gravity maps. The previous major faults are well correlated with the structural map of Jordan published by Bender (1968). 3D modeling of gravity data in the Dead Sea basin (DSB) was used together with existing geological and geophysical information to give a complete structural picture of the basin. The 3D models of the DSB show that the internal structure of the Dead Sea basin (DSB) is controlled by longitudinal faults and the basin is developed as a full graben bounded by sub-vertical faults along its long sides. In the northern planes of the 3D model, the accumulation of Quaternary (salt and marl) and Mesozoic (pre-rift) sediments are thinner than in the central and southern planes of the model. In the northern planes, the thickness of the Quaternary sediments is about 4 km, 5 km in the southern planes and it exceeds 8 km in the central planes of the DSR. The thickness of the pre-rift sediments reaches 10-12 km in the northern and southern planes and exceeds 15 km in the central planes of the DSR. The planes of the 3D models show that the depth to the crystalline basement under the eastern shoulders of the DSR is shallower than those beneath the western shoulders. It is about 3-5 km beneath the eastern shoulders and 7-9 km under the western shoulder of the DSR. The gravity anomaly maps of residual and first derivative gravity delineate the subsurface basins of widely varying size, shape, and depth along the Rift Valley. The basins are created by the combination of the lateral motion along a right-tending step over and normal faulting along the opposite sides. Al Bakura basin occupies the upper Jordanian River valley and extends into the southern Tiberias Lake. Bet Shean basin to the south of Al Bakura basin plunges asymmetrically toward the east. The Damia basin, comprising the central Jordan Valley and Jericho areas to the north of the Dead Sea is shallow basin (~600-800m deep). The Lisan basin is the deepest basin in the Rift. The 3D gravity models indicate a maximum of ~12 km of basin fill. Three basins are found in Wadi Araba area, Gharandal, Timna (Qa'-Taba) and Aqaba (Elat) basin. The three basins become successively wider and deeper to the south. The three regional gravity long E-W profiles (225 km) from the Mediterranean Sea crossing the Rift Valley to the east to the Saudi Arabia borders, show the positive correlation between topography and free air anomaly and strong negative Bouguer anomaly under the central part of the Dead Sea Basin (DSB) and normal regional Bouguer anomaly outside of the DSB in the transform valley. Depth to the top of the bedrock in the under ground of Jordan was calculated from potential field data. The basement crops out in the south west of Jordan and becomes deeper to northwards and eastwards to be about ~ 8 km below ground surface in the Risha area.},
  subject      = {Jordantal},
  language  = {en}
}
@phdthesis{Christensen2003,
  author    = {Christensen, Morten Overby},
  title     = {Dynamics of human DNA Topoisomerases I and II},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-4927},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {The first goal of this study was to develop cell lines with a stable expression of bio-fluorescent topo II and topo I. This was successfully achieved using a bicistronic vector system. Control experiments showed that proteins of expected size were expressed, and that GFP-tagged topos I, IIa, and IIb were active in the cells and fully integrated in the endogenous pools of the enzymes. These cell-lines provided a novel tool for investigating the cell biology of human DNA topoisomerases. Our most important finding was, that both types of mammalian topoisomerases are entirely mobile proteins that are in continuous and rapid flux between all compartments of the nucleus and between the cytososl and the chromosomes of mitotic cells. This was particularly surprising with regard to topo II, which is considered to be a structural component of the nuclear matrix and the chromosome scaffold. We must conclude that if this was the case, then these architectural structures appear to be much more dynamic than believed until now. In this context it should also be mentioned, that the alignment of topo II with the central axes of the chromosome arms, which has until now been considered a hall-mark of the enzyme's association with the chromosomal scaffold, is not seen in vivo and can be demonstrated to be to some extent an artefact of immunohistochemistry. Furthermore, we show that the two isoforms of topo II (a and b) have a different localisation during mitotic cell division, supporting the general concept that topo II functions at mitosis are exclusively assigned to the a-form, whereas at interphase the two isoenzymes work in concert. Despite unrestricted mobility within the entire nuclear space, topoisomerases I and II impose as mostly nucleolar proteins. We show that this is due to the fact that in the nucleoli they are moving slower than in the nucleoplasm. The decreased nucleolar mobility cannot be due to DNA-interactions, because compounds that fix topoisomerases to the DNA deplete them from the nucleoli. Interestingly, the subnucleolar distribution of topoisomerases I and II was complementary. The type II enzyme filled the entire nucleolar space, but excluded the fibrial centers, whereas topo I accumulated at the fibrial centers, an allocation directed by the enzyme's N-terminus. During mitosis, it also mediates association with the nucleolar organising regions of the acrocentric chromosomes. Thus, topo I stays associated with the rDNA during the entire cell-cycle and consistently colocalizes there with RNA-polymerase I. Finally, we show that certain cancer drugs believed to act by stabilising covalent catalytic DNA-intermediates of topoisomerases, do indeed immobilize the enzymes in living cells. Interestingly, these drugs do not target topoisomerases in the nucleoli but only in the nucleoplasm.},
  subject      = {Mensch},
  language  = {en}
}
@phdthesis{Sitaru2003,
  author    = {Sitaru, Ana Gabriela},
  title     = {Modulation of the T cell response with MHC class I peptides and their analogues},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-4561},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2003},
  abstract  = {Transplantation is now firmly established as a therapeutic approach to extend and improve the life of patients in the final stages of organ failure. It has been demonstrated that transplantation between genetically non-identical individuals leads to the activation of the recipient's alloimmune response as a major determinant of transplant outcome. T cell recognition of foreign MHC molecules plays a key role in initiating and sustaining allograft rejection. To prevent the risk of rejection, patients are given immunosuppressive drugs, which are non-specific and have major side-effects (infections, malignancies). It has been shown that the alloreactive T cells specifically recognize donor MHC-derived peptides. This implies that it may be possible to develop antigen-specific strategies in order to modulate the alloimmune response by peptide analogues and specifically altered peptide ligands. The purpose of this study was to explore the potential of "recipient-adapted" analogues from the dominant MHC class I peptide to modulate the alloimmune response. Beside the significant role of donor dominant determinants in the rejection process, we tested seven 13-to-24-mer peptides from the Wistar-Furth MHC class I molecule (WF, RT1.Au) for their possible immunogenicity in a fully MHC-mismatched WF to Lewis (LEW, RT1l) rat strain combination. Secondly, the immunodominant allopeptide was selected to generate analogues in order to investigate their modulatory capacity. All peptides were tested in vitro in a standard proliferation assay and in vivo using a heterotopic heart transplantation model. Our findings show that five peptides (P1-P5) were able to induce specific T cell proliferation in LEW responders. Furthermore, we found a hierarchical distribution of the determinants: peptide P1 as a good candidate for the immunodominant determinant, while P2, P3, P4, and P5 as subdominant epitopes and the other two peptides, P6 and P7, as non-immunogenic determinants of WF MHC class I molecule. Furthermore, the dominance of P1 was confirmed by the strong proliferation induced after immunization with a mixture of peptides in the presence of P1. This hierarchical distribution of the proliferative response correlated with the cytokine production. Peptide P1, comprising only 3 allogeneic amino acids (L5, L9, and T10) induced the strongest T cell proliferation and produced high levels of cytokines, especially IL-2 and IFN-g. In addition, the immunodominance of peptide P1 was confirmed by the significant reduction in the allograft survival time in comparison to the non-immunized control animals. Since the TCR Vß repertoire of rejected graft-infiltrating cells in rejected allografts was similar to the profile observed after in vitro restimulation of P1-primed T cells, we concluded that peptide P1 is able to activate the alloreactive T cell population. Our results demonstrate the particular role of the dominant peptide P1 (residues 1-19) in the allograft rejection in WF to LEW rat strain combination. In the second set of experiments, we investigated the fine specificity of the dominant peptide P1-activated T cells using peptide analogues from P1. The "recipient-adapted" analogues were designed by changing the allogeneic RT1.Au amino acids (L5, L9, T10) one-by-one with the correspondent syngeneic RT1.Al amino acids (M5, D9, I10) in the sequence of peptide P1. The six peptide analogues (A1.1-A1.6) consisting of either one or two allogeneic amino acids were able to induce a specific T cell proliferative response and cytokine production. Analogue A1.5 with only one allogeneic amino acid (L5) was of particular interest because it induced a low T cell proliferation and high cytokine levels, especially IL-4 and IL-10. In addition, immunization with A1.5 did not influence the allograft survival time in comparison to the non-immunized LEW recipients. A1.5 was the only analogue able to down-regulate the proliferation of P1-primed T cells. Our results reveal that A1.5 is an MHC competitor as confirmed by the in vitro MHC competition assay and the inhibition of the negative effect of P1 on the allograft survival time when recipients were immunized with a mixture of P1 and A1.5. These findings suggest that it is possible to design peptide analogues, such as A1.5, which do not stimulate the dominant peptide P1-specific T cell population and even more, are able to block its presentation in the MHC molecule. In all, the results indicate that the specific suppression of indirect allorecognition can be achieved by using peptide analogues of the dominant allopeptide.},
  language  = {en}
}