@phdthesis{Gerold2011,
  author    = {Gerold, Kay},
  title     = {CTLA4 and CLEC16A in Type 1 Diabetes - Looking behind the association},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-66617},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Type 1 diabetes is an autoimmune disease that leads to the destruction of insulin-producing pancreatic beta cells and consequently to hyperglycemia. In the last 60 years, the prevalence of type 1 diabetes has been increasing constantly and is predicted to continue rising. About 80\% of the disease risk is attributable to the genetic variation. Thanks to genome wide association studies the number of known disease-associated polymorphisms climbed from five to 53 in the last 10 years. As these studies reveal possible candidate genes but not underlying mechanisms we strove to take the next step and explore the association of two genes suggested by these studies with type 1 diabetes. As a method of choice we decided to use lentiviral RNAi in non obese diabetic (NOD) mice, a widely-used model for type 1 diabetes, introducing a shRNA directed against the target message into the genome of this mouse strain via a lentivirus. This allowed us to study the partial loss-of-function of the target gene within the context of diabetes, directly seeing its effect on autoimmune mechanisms. In this thesis we examined two different genes in this manner, Ctla4 and Clec16a. A type 1 diabetes associated polymorphism in the CTLA4 gene had been found to alter the splicing ratio of its variants soluble CTLA-4 (sCTLA-4) and full length CTLA-4, the associated allele producing less sCTLA-4 than the protective allele. We mimicked this effect by specifically targeting the sCtla4 mRNA via lentiviral RNAi in the NOD model. As a result we could confirm the reduction of sCTLA-4 to accelerate type 1 diabetes development. Furthermore we could show a function of sCTLA-4 in regulatory T cells, more specifically at least partly in their ability to modulate costimulation by antigen presenting cells. The second candidate gene, Clec16a was targeted with the shRNA in a way that was designed to knock down most splice variants. As the gene function and the effect of the associated SUMMARY 10 polymorphism was unknown, we reasoned this method to be feasible to investigate its role in type 1 diabetes. The knockdown of Clec16a in NOD mice resulted in an almost complete protection from diabetes development that could be attributed to T cells dysfunction. However, as expression patterns and a study of the Drospophila orthologue suggested a possible role of CLEC16A in antigen presentation we also examined antigen presenting cells in the thymus and periphery. Although we did not detect any effect of the knockdown on peripheral antigen presenting cells, thymic epithelial cells were clearly affected by the loss of CLEC16A, rendering them more activated and shifting the ratio of cortical to medullary epithelial cells in favor of cortical cells. We therefore suggest a role of CLEC16A in the selection of T cells, that needs, however, to be further investigated. In this thesis we provided a feasible and fast method to study function of genes and even of single splice variants within the NOD mouse model. We demonstrate its usefulness on two candidate genes associated with type 1 diabetes by confirming and unraveling the cause of their connection to the disease.},
  subject      = {Diabetes mellitus},
  language  = {en}
}
@phdthesis{Roth2011,
  author    = {Roth, Heide Marie},
  title     = {Nucleotide Excision Repair: From Recognition to Incision of damaged DNA},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57098},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {The Nucleotide Excision Repair (NER) pathway is able to remove a vast diversity of structurally unrelated DNA lesions and is the only repair mechanism in humans responsible for the excision of UV induced DNA damages. The NER mechanism raises two fundamental questions: 1) How is DNA damage recognition achieved discriminating damaged from non damaged DNA? 2) How is DNA incision regulated preventing endonucleases to cleave DNA non specifically but induce and ensure dual incision of damaged DNA? Thus, the aim of this work was to investigate the mechanisms leading from recognition to incision of damaged DNA. To decipher the underlying process of damage recognition in a prokaryotic model system, the intention of the first part of this work was to co crystallize the helicase UvrB form Bacillus caldotenax together with a DNA substrate comprising a fluorescein adducted thymine as an NER substrate. Incision assays were performed to address the question whether UvrB in complex with the endonuclease UvrC is able to specifically incise damaged DNA employing DNA substrates with unpaired regions at different positions with respect to the DNA lesion. The results presented here indicate that the formation of a specific pre incision complex is independent of the damage sensor UvrA. The preference for 5' bubble substrate suggests that UvrB is able to slide along the DNA favorably in a 5' → 3' direction until it directly encounters a DNA damage on the translocating strand to then recruit the endonuclease UvrC. In the second part of this work, the novel endonuclease Bax1 from Thermoplasma acidophilum was characterized. Due to its close association to archaeal XPB, a potential involvement of Bax1 in archaeal NER has been postulated. Bax1 was shown to be a Mg2+ dependent, structure specific endonuclease incising 3' overhang substrates in the single stranded region close to the ssDNA/dsDNA junction. Site directed mutagenesis of conserved amino acids was employed to identify putative active site residues of Bax1. In complex with the helicase XPB, however, incision activity of Bax1 is altered regarding substrate specificity. The presence of two distinct XPB/Bax1 complexes with different endonuclease activities indicates that XPB regulates Bax1 incision activity providing insights into the physical and functional interactions of XPB and Bax1.},
  subject      = {DNS-Reparatur},
  language  = {en}
}
@phdthesis{Salvador2011,
  author    = {Salvador, Ellaine Riciel P.},
  title     = {Characterization of Asymptomatic Bacteriuria (ABU) Escherichia coli Isolates: virulence traits and host-pathogen interactions},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71283},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Urinary tract infection (UTI) is one of the most serious health problems worldwide. It accounts for a million hospital visits annually in the United States. Among the many uropathogenic bacteria, uropathogenic Escherichia coli (UPEC) is the most common causative agent of UTI. However, not all E. coli that inhabit the urinary tract can cause UTI. Some of them thrive for long periods of time in the urinary bladder without causing overt symptoms of infection. This carrier state is called asymptomatic bacteriuria (ABU). E. coli ABU isolates can live in the host without inducing host response due to deletions, insertions and point mutations in the genome leading to the attenuation of virulence genes. They therefore behave in the same way as commensals. Since bacteria that inhabit the urinary tract are said to originate from the lower intestinal tract and ABU behave in a similar way as commensals, this study compared various phenotypic and genotypic characteristics of ABU and commensal E. coli fecal isolates. The two groups did not show a strict clustering with regards to phylogenetic lineage since there appears to be overlaps in their distribution in some clonal complexes. In addition, it was observed that the UPEC virulence genes were more frequently inactivated in ABU than in fecal isolates. Hence, ABU tend to have less functional virulence traits compared to the fecal isolates. The ABU model organism E. coli 83972 which is known not only for its commensal behavior in the urinary bladder but its ability to outcompete other bacteria in the urinary tract is currently being used as prophylactic treatment in patients who have recurrent episodes of UTI at the University Hospital in Lund, Sweden. The pilot studies showed that upon deliberate long-term colonization of the patients with E. coli 83972, they become protected from symptomatic UTI. In this study, the phenotypic and genotypic characteristics of eight re-isolates taken from initially asymptomatically colonized patients enrolled in the deliberate colonization study who reported an episode of symptoms during the colonization period were investigated. Two out of the eight re-isolates were proven to be a result of super infection by another uropathogen. Six re-isolates, on the other hand, were E. coli 83972. The urine re-isolates confirmed to be E. coli 83972 were phenotypically heterogeneous in that they varied in colony size as well as in swarming motility. Four of these re-isolates were morphologically homogenous and similar to the parent isolate E. coli 83972 whereas one of them appeared phenotypically heterogenous as a mixture of smaller and normal-sized colonies. Still another re-isolate phenotypically resembled small colony variants. Meanwhile, three of the six re-isolates did not differ from the parent isolate with regards to motility. On the other hand, three exhibited a markedly increased motility compared to the parent isolate. Transcriptome analysis demonstrated the upregulation of a cascade of genes involved in flagellar expression and biosynthesis in one of the three motile re-isolates. However, upon further investigation, it was found out that the expression of flagella had no effect on bacterial adhesion to host cells in vitro as well as to the induction of host inflammatory markers. Thus, this implies that the increased motility in the re-isolates is used by the bacteria as a fitness factor for its benefit and not as a virulence factor. In addition, among the various deregulated genes, it was observed that gene regulation tends to be host-specific in that there is no common pattern as to which genes are deregulated in the re-isolates. Taken together, results of this study therefore suggest that the use of E. coli 83972 for prophylactic treatment of symptomatic UTI remains to be very promising.},
  subject      = {Escherichia coli},
  language  = {en}
}
@phdthesis{Simon2011,
  author    = {Simon, Christian Marc},
  title     = {Effects of the neurotrophic factors CNTF and IGF-1 in mouse models for spinal muscular atrophy and diabetic neuropathy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70207},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {In this study I investigate the role of Schwann cell and axon-derived trophic signals as modifiers of axonal integrity and sprouting in motoneuron disease and diabetic neuropathy (DNP). The first part of this thesis focuses on the role of the Schwann-cell-derived ciliary neurotrophic factor (CNTF) for compensatory sprouting in a mouse model for mild spinal muscular atrophy (SMA). In the second part, the role of the insulin-like growth factor 1 (IGF-1) and its binding protein 5 (IGFBP-5) is examined in the peripheral nerves of patients with DNP and in two corresponding mouse models. Proximal SMA is caused by homozygous loss or mutation of the SMN1 gene on human chromosome 5. The different forms of SMA can be divided into four groups, depending on the levels of SMN protein produced from a second SMN gene (SMN2) and the severity of the disease. Patients with milder forms of the disease, type III and type IV SMA, normally reach adulthood and regularly show enlargement of motor units, signifying the reinnervation of denervated muscle fibers. However, the underlying mechanisms are not understood. Smn+/- mice, a model of type III/IV SMA, are phenotypically normal, but they reveal progressive loss of motor neurons and denervation of motor endplates starting at 4 weeks of age. The progressive loss of spinal motor neurons reaches 50\% at 12 months but muscle strength is not reduced. The first evidence for axonal sprouting as a compensatory mechanism in these animals was the more than 2-fold increase in amplitude of single motor unit action potentials (SMUAP) in the gastrocnemius muscle. Confocal analysis confirmed pronounced sprouting of innervating motor axons. As CNTF is highly expressed in Schwann cells and known to be involved in sprouting, its role for this compensatory sprouting response and the maintenance of muscle strength in Smn+/- mice was investigated. Deletion of CNTF in this mouse model results in reduced sprouting and decline of muscle strength in Smn+/- Cntf-/- mice. These findings indicate that CNTF is necessary for a sprouting response and thus enhances the size of motor units in skeletal muscles of Smn+/- mice. DNP afflicting motor and sensory nerve fibers is a major complication in diabetes mellitus. The underlying cellular mechanisms of motor axon degeneration are poorly understood. IGFBP-5, an inhibitory binding protein for IGF-1, is highly upregulated in peripheral nerves in patients with DNP. The study investigates the pathogenic relevance of this finding in transgenic mice overexpressing IGFBP-5 in motor axons. These mice develop motor axonopathy similar to that seen in DNP. Motor axon degeneration is also observed in mice in which the IGF-1 receptor (IGF-1R) was conditionally depleted in motoneurons, indicating that reduced activity of IGF-1 on IGF-1R in motoneurons is responsible for the observed effect. These data provide evidence that elevated expression of IGFBP-5 in diabetic nerves reduces the availability of IGF-1 for IGF-1R on motor axons leading to progressive neurodegeneration, and thus offers novel treatment strategies.},
  subject      = {Spinale Muskelatrophie},
  language  = {en}
}
@phdthesis{Sareen2011,
  author    = {Sareen, Preeti},
  title     = {Visual attention in Drosophila melanogaster},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69616},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {There is such vast amount of visual information in our surroundings at any time that filtering out the important information for further processing is a basic requirement for any visual system. This is accomplished by deploying attention to focus on one source of sensory inputs to the exclusion of others (Luck and Mangun 2009). Attention has been studied extensively in humans and non human primates (NHPs). In Drosophila, visual attention was first demonstrated in 1980 (Wolf and Heisenberg 1980) but this field remained largely unexplored until recently. Lately, however, studies have emerged that hypothesize the role of attention in several behaviors but do not specify the characteristic properties of attention. So, the aim of this research was to characterize the phenomenon of visual attention in wild-type Drosophila, including both externally cued and covert attention using tethered flight at a torque meter. Development of systematic quantifiable behavioral tests was a key aspect for this which was not only important for analyzing the behavior of a population of wild-type flies but also for comparing the wild-type flies with mutant flies. The latter would help understand the molecular, genetic, and neuronal bases of attention. Since Drosophila provides handy genetic tools, a model of attention in Drosophila will serve to the greater questions about the neuronal circuitry and mechanisms involved which might be analogous to those in primates. Such a model might later be used in research involving disorders of attention. Attention can be guided to a certain location in the visual field by the use of external cues. Here, using visual cues the attention of the fly was directed to one or the other of the two visual half-fields. A simple yet robust paradigm was designed with which the results were easily quantifiable. This paradigm helped discover several interesting properties of the cued attention, the most substantial one being that this kind of external guidance of attention is restricted to the lower part of the fly's visual field. The guiding cue had an after-effect, i.e. it could occur at least up to 2 seconds before the test and still bias it. The cue could also be spatially separated from the test by at least 20° and yet attract the attention although the extent of the focus of attention (FoA) was smaller than one lower visual half-field. These observations excluded the possibility of any kind of interference between the test and the cue stimuli. Another interesting observation was the essentiality of continuous visibility of the test stimulus but not the cue for effective cuing. When the contrast of the visual scene was inverted, differences in response frequencies and cuing effects were observed. Syndirectional yaw torque responses became more frequent than the antidirectional responses and cuing was no longer effective in the lower visual field with inverted contrast. Interestingly, the test stimulus with simultaneous displacement of two stripes not only effectuated a phasic yaw torque response but also a landing response. A 50 landing response was produced in more than half of the cases whenever a yaw torque response was produced. Elucidation of the neuronal correlates of the cued attention was commenced. Pilot experiments with hydroxyurea (HU) treated flies showed that mushroom bodies were not required for the kind of guidance of attention tested in this study. Dopamine mutants were also tested for the guidance of attention in the lower visual field. Surprisingly, TH-Gal4/UAS-shits1 flies flew like wild-type flies and also showed normal optomotor response during the initial calibration phase of the experiment but did not show any phasic yaw torque or landing response at 18 °C, 25 °C or 30 °C. dumb2 flies that have almost no D1 dopamine receptor dDA1 expression in the mushroom bodies and the central complex (Kim et al. 2007) were also tested and like THGal4/ UAS-shits1 flies did not show any phasic yaw torque or landing response. Since the dopamine mutants did not show the basic yaw torque response for the test the role of dopamine in attention could not be deduced. A different paradigm would be needed to test these mutants. Not only can attention be guided through external cues, it can also be shifted endogenously (covert attention). Experiments with the windows having oscillating stripes nicely demonstrated the phenomenon of covert attention due to the production of a characteristic yaw torque pattern by the flies. However, the results were not easily quantifiable and reproducible thereby calling for a more systematic approach. Experiments with simultaneous opposing displacements of two stripes provide a promising avenue as the results from these experiments showed that the flies had a higher tendency to deliver one type of response than when the responses would be produced stochastically suggesting that attention increased this tendency. Further experiments and analysis of such experiments could shed more light on the mechanisms of covert attention in flies.},
  subject      = {Visuelle Aufmerksamkeit},
  language  = {en}
}
@phdthesis{Eschbach2011,
  author    = {Eschbach, Claire},
  title     = {Classical and operant learning in the larvae of Drosophila melanogaster},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70583},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {In dieser Doktorarbeit studiere ich einige psychologische Aspekte im Verhalten der Drosophila, insbesondere von Drosophila Larven. Nach einer Einleitung, in der ich den wissenschaftlichen Kontext darstelle und die Mechanismen der olfaktorischen Wahrnehmung sowie des klassichen und operanten Lernens beschreibe, stelle ich die verschiedenen Experimente meiner Doktorarbeit vor. Wahrnehmung Das zweite Kapitel behandelt die Art, in der adulte Drosophila zwischen Einzeld{\"u}ften und Duftgemischen generaliseren. Ich habe gefunden, daß die Fliegen eine Mischung aus zwei D{\"u}ften als gleich verschieden von ihren beiden Elementen wahrnehmen; und daß die Intensit{\"a}t sowie die chemisch-physikalische Natur der Elemente das Ausmass der Generalisierung zwischen der Mischung und ihren beiden Elementen beeinflusst. Diese Entdeckungen sollten f{\"u}r die weitere Forschung anregend sein, wie zum Beispiel zum functional imaging. Ged{\"a}chtnis Das dritte Kapitel stellt die Etablierung eines neuen Protokolls zur klassischen Konditionierung bei Drosophila Larven dar. Es handelt sich um Experimente, bei denen ein Duft mit einer mechanischen St{\"o}rung als Strafreiz verkn{\"u}pft wird. Das Protokoll wird einen Vergleich zwischen zwei Arten vom aversiven Ged{\"a}chtnissen (Geschmack vs. mechanische St{\"o}rung als Strafreize) erm{\"o}glichen, einschliesslich eines Vergleiches ihrer neurogenetischen Grundlagen; zudem kann nun geforscht werden, ob die jeweiligen Ged{\"a}chtnisse spezifisch f{\"u}r die Art des verwendeten Strafreizes sind. Selbstgestaltung Das vierte Kapitel umfasst unsere Versuche, operantes Ged{\"a}chtnis bei Drosophila Larven zu beobachten. Zumindest f{\"u}r die unmittelbar ersten Momente des Tests konnte ich zeigen, dass die Larven ihr Verhalten entsprechend dem Training ausrichten. Dieses Ged{\"a}chtnis scheint jedoch im Laufe des Tests schnell zu verschwinden. Es ist daher geraten, diese Ergebnisse {\"u}ber operantes Lernen zu wiederholen, eventuell das experimentelle Protokoll zu verbessern, um so eine systematische Analyse der Bedingungen und Mechanismen f{\"u}r das operante Lernen bei der Drosophila Larve zu erlauben. Im f{\"u}nften Kapitel verwende ich die im Rahmen des vierten Kapitels entwickelten Methoden f{\"u}r eine Analyse der Fortbewegung der Larven. Ich habe insbesondere die Wirkung des pflanzlichen ‚cognitive enhancers' Rhodiola rosea untersucht, sowie die Auswirkungen von Mutationen in den Genen, welche f{\"u}r Synapsin und SAP47 kodieren; schliesslich habe ich getestet, ob die Geschmacksqualit{\"a}t der Testsituation lokomotorische Parameter ver{\"a}ndert. Diese Dissertation erbringt also eine Reihe neuer Aspekte zur Psychologie der Drosophila und wird hoffentlich in diesem Bereich der Forschung neue Wege {\"o}ffnen.},
  subject      = {Lernen},
  language  = {en}
}
@phdthesis{Pletinckx2011,
  author    = {Pletinckx, Katrien},
  title     = {Dendritic cell maturation and instruction of CD4+ T cell tolerance in vitro},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67375},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Effective T cell immunity was believed to occur by mature DC, whereas tolerogenicity was attributed strictly to immature DC phenotypes. However, intermediate DC maturation stages were identified conditioned by inflammatory mediators like TNF. Furthermore, the T cell tolerance mechanisms are dependent on distinct modes and intensities of co-stimulation. Therefore, in this study it was addressed how distinct DC maturation signatures instruct CD4+ T cell tolerance mechanisms. DC acquire antigens from apoptotic cells for self-peptide-MHC presentation and functionally adapt presumed tolerogenic DC phenotypes. Here, immature murine bone-marrow derived DC representing both inflammatory and conventional DC subsets adapted a maturationresistant DC signature upon apoptotic cell recognition but no additional tolerogenic features. Immature DC instruct CD4+ FoxP3+ regulatory T cells in a TGF-β prone micro-environment or generate anergic CD4+ T cells hampered in the TCR-induced proliferation and IL-2 secretion. Secondary stimulation of such anergic CD4+ T cells by immature DC increased primarily IL-10 production and conferred regulatory function. These IL-10+ regulatory T cells expressed high levels of CTLA-4, which is potently induced by immature DC in particular. Data in this work showed that anergic T cells can be re-programmed to become IL-10+ regulatory T cells upon ligation of CTLA-4 and CD28 signalling cascades by B7 costimulatory ligands on immature DC. In contrast, semi-mature DC phenotypes conditioned by the inflammatory mediator TNF prevented autoimmune disorders by induction of IL-10+ Th2 responses as demonstrated previously. Here, it was shown that TNF as an endogenous maturation stimulus and pathogenic Trypanosoma brucei variant-specific surface glycoproteins (VSG) induced highly similar DC gene expression signatures which instructed default effector Th2 responses. Repetitive administration of the differentially conditioned semi-mature DC effectively skewed T cell immunity to IL-10+ Th2 cells, mediating immune deviation and suppression. Collectively, the data presented in this work provide novel insights how immature and partially mature DC phenotypes generate T cell tolerance mechanisms in vitro, which has important implications for the design of effective DC-targeted vaccines. Unravelling the DC maturation signatures is central to the long-standing quest to break tolerance mimicked by malignant tumours or re-establish immune homeostasis in allergic or autoimmune disorders.},
  subject      = {Dendritische Zelle},
  language  = {en}
}
@phdthesis{Wolski2011,
  author    = {Wolski, Stefanie Carola},
  title     = {Structural and functional characterization of nucleotide excision repair proteins},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67183},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {XPD is a 5'-3' helicase of the superfamily 2. As part of the transcription factor IIH it functions in transcription initiation and nucleotide excision repair. This work focus on the role of XPD in nucleotide excision repair. NER is a DNA repair pathway unique for its broad substrate range. In placental mammals NER is the only repair mechanism able to remove lesions induced by UV-light. NER can be divided into four different steps that are conserved between pro- and eukaryotes. Step 1 consists of the initial damage recognition, during step 2 the putative damage is verified, in step 3 the verified damage is excised and in the 4th and final step the resulting gap in the DNA is refilled. XPD was shown to be involved in the damage verification step. It was possible to solve the first apo XPD structure by a MAD approach using only the endogenous iron from the iron sulfur cluster. Based on the apo XPD structure several questions arise: where is DNA bound? Where is DNA separated? How is damage verification achieved? What is the role of the FeS cluster? These questions were addressed in this work. Hypothesis driven structure based functional mutagenesis was employed and combined with detailed biochemical characterization of the variants. The variants were analyzed by thermal unfolding studies to exclude the possibility that the overall stability could be affected by the point mutation. DNA binding assays, ATPase assays and helicase assays were performed to delineate amino acid residues important for DNA binding, helicase activity and damage recognition. A structure of XPD containing a four base pair DNA fragment was solved by molecular replacement. This structure displays the polarity of the translocated strand with respect to the helicase framework. Moreover the properties of the FeS cluster were studied by electron paramagnetic resonance to get insights into the role of the FeS cluster. Furthermore XPD from Ferroplasma acidarmanus was investigated since it was shown that it is stalled at CPD containing lesions. The data provide the first detailed insight into the translocation mechanism of a SF2B helicase and reveal how polarity is achieved. This provides a basis for further anlayses understanding the combined action of the helicase and the 4Fe4S cluster to accomplish damage verification within the NER cascade.},
  subject      = {DNS-Reparatur},
  language  = {en}
}
@phdthesis{Angermeier2011,
  author    = {Angermeier, Hilde Gabriele},
  title     = {Molecular and ecological investigations of Caribbean sponge diseases},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-56855},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {W{\"a}hrend gewinnbringende Assoziationen von Schw{\"a}mmen mit Mikroorganismen in den letzten Jahren viel Aufmerksamkeit erhalten haben, wurde weit weniger in die Interaktion von Schw{\"a}mmen mit m{\"o}glicherweise pathogenen Mikroben investiert. Somit war es das Ziel dieser Studie zwei ausgew{\"a}hlte Karibische Schwammkrankheiten namens „Sponge Orange Band" und „Sponge White Patch" mittels {\"o}kologischer und molekularer Methoden zu untersuchen. Die Sponge Orange Band (SOB) Erkrankung bef{\"a}llt den bedeutenden karibischen Fass-Schwamm Xestospongia muta, der zu den bakterienhaltigen (HMA) Schw{\"a}mmen gez{\"a}hlt wird, w{\"a}hrend die Sponge White Patch (SWP) Erkrankung den h{\"a}ufig vorkommenden Seil-Schwamm Amphimedon compressa betrifft, der zu den bakterienarmen (LMA) Schw{\"a}mmen geh{\"o}rt. F{\"u}r beide Karibischen Schwammkrankheiten konnte ich einen Krankheitsverlauf beschreiben, der mit massiver Gewebszerst{\"o}rung und dem Verlust charakteristischer mikrobieller Signaturen einhergeht. Obwohl ich zeigen konnte, dass zus{\"a}tzliche Bakterienarten die gebleichten Schwammbereiche kolonisieren, lieferten meine Infektionsversuche in beiden F{\"a}llen keinen Beweis f{\"u}r die Beteiligung eines mikrobiellen Pathogens als Krankheitserreger. Somit liegen die eigentlichen Ausl{\"o}ser der Erkrankungen Sponge Orange Band als auch Sponge White Patch noch immer im Dunkeln.},
  subject      = {Meeresschw{\"a}mme},
  language  = {en}
}
@phdthesis{OenalHartmann2011,
  author    = {{\"O}nal-Hartmann, Cigdem},
  title     = {Emotional Modulation of Motor Memory Formation},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64838},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Hintergr{\"u}nde: Wie eine Vielzahl von Studien belegt, kann das explizite Ged{\"a}chtnis, das die bewusste Erinnerung an enkodierte Informationen beinhaltet, durch Emotionen beeinflusst werden, und zwar {\"u}ber den Einfluss auf verschiedene Verarbeitungsebenen (Enkodierung, Konsolidierung, Abruf usw.). Bisher wenig untersucht ist, ob und wie Emotionen Vorg{\"a}nge der motorischen Ged{\"a}chtnisbildung, die nicht auf bewusster Erinnerung beruhen und sich stattdessen durch Ver{\"a}nderungen im Verhalten darstellen, modulieren. Experiment 1: Das Ziel des ersten Experimentes war es, den Einfluss von Emotionen auf motorisches Lernen zu untersuchen. Vier Gruppen von Probanden mussten in einer motorischen Lernaufgabe schnelle, seitliche Bewegungen mit dem Daumen ausf{\"u}hren. W{\"a}hrend dieser Aufgabe h{\"o}rten die Probanden emotionale Kl{\"a}nge, die in Valenz und Arousal variierten: 1. Valenz negativ/ Arousal niedrig (V-/A-), 2. Valenz negativ/ Arousal hoch (V-/A+), 3. Valenz positiv/ Arousal niedrig (V+/A-), 4. Valenz positiv/ Arousal hoch (V+/A+). Die deskriptive Analyse aller Daten sprach f{\"u}r beste Ergebnisse f{\"u}r das motorische Lernen in der Bedingung V-/A-, aber die Unterschiede zwischen den Bedingungen waren nicht signifikant. Die Interaktion zwischen Valenz und Arousal emotionaler T{\"o}ne scheint demnach motorische Enkodierungsprozesse zu modulieren, jedoch m{\"u}ssen zuk{\"u}nftige Studien mit unterschiedlichen emotionalen Stimuli die Annahme weiter untersuchen, dass negative Stimuli mit niedrigem Arousal w{\"a}hrend der Enkodierung einen f{\"o}rdernden Effekt auf das motorische Kurzzeitged{\"a}chtnis haben. Experiment 2: Die Absicht des zweiten Experimentes war es, die Auswirkungen emotionaler Interferenzen auf die Konsolidierung beim Sequenzlernen zu untersuchen. Sechs Gruppen von Probanden trainierten zuerst in getrennten Sitzungen eine SRTT-Aufgabe (serial reaction time task). Um die Konsolidierung der neu erlernten Fertigkeit zu modulieren, wurden die Probanden nach dem Training einer von drei unterschiedlichen Klassen emotionaler Stimuli (positiv, negativ oder neutral) ausgesetzt. Diese bestanden aus einem Set emotionaler Bilder, die mit emotional kongruenten Musikst{\"u}cken oder neutralen Kl{\"a}ngen kombiniert waren. Bei den Probandengruppen wurde die emotionale Interferenz nach zwei unterschiedlichen Zeitintervallen realisiert, entweder direkt nach der Trainingssitzung oder sechs Stunden sp{\"a}ter. 72 Stunden nach der Trainingssitzung wurde jede Gruppe erneut mit der SRTT-Aufgabe getestet. Die Leistung in diesem Nachtest wurde mittels Reaktionszeit und Genauigkeit bei der Ausf{\"u}hrung der Zielsequenz analysiert. Die emotionale Interferenz beeinflusste weder die Nachtestergebnisse f{\"u}r die Reaktionszeit noch die f{\"u}r die Genauigkeit. Allerdings konnte eine Steigerung der expliziten Sequenzerkennung durch erregende negative Stimuli festgestellt werden, wenn diese direkt nach der ersten Trainingseinheit (0h) dargeboten wurden. Diese Ergebnisse lassen vermuten, dass die Konsolidierung der expliziten Aspekte prozeduralen Lernens in einer st{\"a}rkeren Wechselwirkung mit emotionalen Interferenzen stehen k{\"o}nnte als die der impliziten Aspekte. Die Konsolidierung unterschiedlicher Ebenen des Fertigkeitserwerbs k{\"o}nnte demnach von unterschiedlichen Mechanismen gesteuert werden. Da Performanz und explizites Sequenzerkennen nicht korrelierten, vermuten wir, dass implizite und explizite Modalit{\"a}ten bei der Durchf{\"u}hrung der SRTT-Aufgabe nicht komplement{\"a}r sind. Experiment 3: Es sollte untersucht werden, ob es eine Pr{\"a}ferenz der linken Gehirnhemisph{\"a}re bei der Kontrolle von Flexionsreaktionen auf positive Stimuli gibt und der rechten Hemisph{\"a}re bei der Kontrolle von Extensionsreaktionen auf negative Stimuli. Zu diesem Zweck sollten rechtsh{\"a}ndige Probanden einen Joystick zu sich ziehen oder von sich weg dr{\"u}cken, nachdem sie einen positiven oder negativen Stimulus in ihrem linken oder rechten Gesichtsfeld gesehen hatten. Die Flexionsreaktionen waren bei positiven Stimuli schneller, Extensionsreaktion hingegen bei negativen Stimuli. Insgesamt war die Performanz am schnellsten, wenn die emotionalen Stimuli im linken Gesichtsfeld pr{\"a}sentiert wurden. Dieser Vorrang der rechten Gehirnhemisph{\"a}re war besonders deutlich f{\"u}r negative Stimuli, wohingegen die Reaktionszeiten auf positive Bilder keine hemisph{\"a}rische Differenzierung zeigten. Wir konnten keine Interaktion zwischen Gesichtsfeld und Reaktionstyp belegen, auch fand sich keine Dreifachinteraktion zwischen Valenz, Gesichtsfeld und Reaktionstyp. In unserem experimentellen Kontext scheint die Interaktion zwischen Valenz und Gesichtsfeld st{\"a}rker zu sein als die Interaktion zwischen Valenz und motorischem Verhalten. Auf Grund dieser Ergebnisse vermuten wir, dass unter gewissen Bedingungen eine Hierarchisierung der asymmetrischen Muster Vorrang hat, die m{\"o}glicherweise andere vorhandene Asymmetrien maskieren k{\"o}nnte.},
  subject      = {Motorisches Lernen},
  language  = {en}
}
@phdthesis{ZelmanFemiak2011,
  author    = {Zelman-Femiak, Monika},
  title     = {Single Particle Tracking ; Membrane Receptor Dynamics},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-65420},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Single-molecule microscopy is one of the decisive methodologies that allows one to clarify cellular signaling in both spatial and temporal dimentions by tracking with nanometer precision the diffusion of individual microscopic particles coupled to relevant biological molecules. Trajectory analysis not only enables determination of the mechanisms that drive and constrain the particles motion but also to reveal crucial information about the molecule interaction, mobility, stoichiometry, all existing subpopulations and unique functions of particular molecules. Efficacy of this technique depends on two problematic issues the usage of the proper fluorophore and the type of biochemical attachment of the fluorophore to a biomolecule. The goal of this study was to evolve a highly specific labeling method suitable for single molecule tracking, internalization and trafficking studies that would attain a calculable 1:1 fluorophore-to-receptor stoichiometry. A covalent attachment of quantum dots to transmembrane receptors was successfully achieved with a techinque that amalgamates acyl carrier protein (ACP) system as a comparatively small linker and coenzyme A (CoA)-functionalized quantum dots. The necessity of optimization of the quantum dot usage for more precise calculation of the membrane protein stoichiometries in larger assemblies led to the further study in which methods maximizing the number of signals and the tracking times of diverse QD types were examined. Next, the optimized techniques were applied to analyze behavior of interleukin-5 β-common chain receptor (IL-5Rβc) receptors that are endogenously expressed at low level on living differentiated eosinophil-like HL-60 cells. Obtained data disclosed that perused receptors form stable and higher order oligomers. Additionally, the mobility analysis based on increased in number (>10\%) uninterrupted 1000-step trajectories revealed two patterns of confined motion. Thereupon methods were developed that allow both, determination of stoichiometries of cell surface protein complexes and the acquisition of long trajectories for mobility analysis. Sequentially, the aforementioned methods were used to scrutinize on the mobility, internalization and recycling dynamics characterization of a G protein-coupled receptor (GPCRs), the parathyroid hormone receptor (PTHR1) and several bone morphogenetic proteins (BMPs), a member of the TGF-beta superfamily of receptors. These receptors are two important representatives of two varied membrane receptor classes. BMPs activate SMAD- and non-SMAD pathways and as members of the transforming growth factor β (TGF-β) superfamily are entailed in the regulation of proliferation, differentiation, chemotaxis, and apoptosis. For effective ligand induced and ligand independent signaling, two types of transmembrane serine/threonine kinases, BMP type I and type II receptors (BMPRI and BMPRII, respectively) are engaged. Apparently, the lateral mobility profiles of BMPRI and BMPRII receptors differ markedly, which determinate specificity of the signal. Non-SMAD signaling and subsequent osteoblastic differentiation of precursor cells particularly necessitate the confinement of the BMP type I receptor, resulting in the conclusion that receptor lateral mobility is a dominative mechanism to modulate SMAD versus non-SMAD signaling during differentiation. Confined motion was also predominantly observed in the studies devoted to, entailed in the regulation of calcium homeostasis and in bone remodeling, the parathyroid hormone receptor (PTHR1), in which stimulation with five peptide ligands, specific fragments of PTH: hPTH(1-34), hPTHrP(107-111)NH2; PTH(1-14); PTH(1-28) G1R19, bPTH(3-34), first four belonging to PTH agonist group and the last to the antagonist one, were tested in the wide concentration range on living COS-1 and AD293 cells. Next to the mobility, defining the internalization and recycling rates of the PTHR1 receptor maintained in this investigation one of the crucial questions. Internalization, in general, allows to diminish the magnitude of the receptor-mediated G protein signals (desensitization), receptor resensitization via recycling, degradation (down-regulation), and coupling to other signaling pathways (e.g. MAP kinases). Determinants of the internalization process are one of the most addressed in recent studies as key factors for clearer understanding of the process and linking it with biological responses evoked by the signal transduction. The internalization of the PTH-receptor complex occurs via the clathrin-coated pit pathway involving β-arrestin2 and is initiated through the agonist occupancy of the PTHR1 leading to activation of adenylyl cyclase (via Gs), and phosphatidylinositol-specific phospholipase Cβ (via Gq). Taken together, this work embodies complex study of the interleukin-5 β-common chain receptor (IL-5Rβc) receptors, bone morphogenetic proteins (BMPs) and the parathyroid hormone receptor with the application of single-molecule microscopy with the newly attained ACP-quantum dot labeling method and standard techniques.},
  subject      = {Einzelmolek{\"u}lmikroskopie},
  language  = {en}
}
@phdthesis{Zanucco2011,
  author    = {Zanucco, Emanuele},
  title     = {Role of oncogenic and wild type B-RAF in mouse lung tumor models},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69603},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Von Wachstumsfaktoren regulierte Signalkaskaden sind Schl{\"u}sselelemente in der Gewebeentwicklung und Geweberegeneration. Eine Deregulation dieser Kaskaden f{\"u}hrt zu Entwicklungsst{\"o}rungen und neoplastischen Krankheiten. F{\"u}r viele humane Krebsformen sind aktivierende Mutationen der Kinasen der RAF Familie verantwortlich. Das erste Projekt dieser Doktorarbeit fokussiert auf der Rolle des B-RAF V600E, welches als eine der am h{\"a}ufigsten vorkommenden Mutantionen in humanen Krebszellen identifiziert worden ist. Um die onkogene Funktion des B-RAF V600E zu untersuchen, haben wir transgene Mauslinien hergestellt, welche das aktivierte Onkogen spezifisch in alveolaren Lungenepithelzellen des Typ II exprimieren. Konstitutive Expression des B-RAF V600E f{\"u}hrte zu einer abnormen alveolaren Epithelzellbildung und zu Emphysem-{\"a}hnlichen L{\"a}sionen. Diese L{\"a}sionen wiesen Zeichen einer Gewebsumstrukturierung auf, oft in Assoziation mit chronischer Inflammation und geringer Inzidenz von Lungentumoren. Die Infiltration der entz{\"u}ndlichen Zellen erfolgte erst nach der Entstehung von Emphysem-{\"a}hnlichen L{\"a}sionen und k{\"o}nnte zur sp{\"a}teren Tumorbildung beigetragen haben. Diese Ergebnisse unterst{\"u}tzen ein Modell, in welchem der kontinuierliche regenerative Prozess eine tumorf{\"o}rdernde Umgebung schafft. Dabei induziert die Aktivit{\"a}t des onkogenen B-RAF eine alveolare St{\"o}rung, welche urs{\"a}chlich verantwortlich ist f{\"u}r den kontinuierlichen regenerativen Prozess. Das zweite Projekt fokussiert auf die Rolle von endogenem (wildtypischen) B-RAF in einem durch onkogenes C-RAF induzierten Maus Lungentumormodell. F{\"u}r unsere Untersuchungen haben wir eine Mauslinie geschaffen, in welcher B-RAF in den C-RAF Lungentumoren konditionell eliminiert werden kann. Eine konditionelle Eliminierung des B-RAF hat die Entstehung von Lungentumoren nicht blockiert, aber zu reduziertem Tumorwachstum gef{\"u}hrt. Dieses reduzierte Tumorwachstum konnte auf eine reduzierte Zellproliferation zur{\"u}ckgef{\"u}hrt werden. Außerdem konnten wir durch die B-RAF Elimination eine Reduktion der Intensit{\"a}t der mitogenen Signalkaskade beobachten. Insgesamt deuten die Ergebnisse darauf hin, dass das onkogene Potential von C-RAF in vivo unabh{\"a}ngig von B-RAF ist und eine Kooperation von B-RAF und C-RAF jedoch f{\"u}r die vollst{\"a}ndige Aktivierung der mitogenen Signalkaskade wichtig ist.},
  subject      = {Lungenkrebs},
  language  = {en}
}
@phdthesis{Rajaraman2011,
  author    = {Rajaraman, Gnana Oli},
  title     = {Oxidative stress: Role in genomic damage and disease},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64869},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Bei einem Ungleichgewicht zwischen reaktiven Sauerstoffspezies (ROS) und endogenen Antioxidantien (Glutathion (GSH), Superoxiddismutase (SOD), Katalase etc.) ist der oxidative Stress erh{\"o}ht, was zur Oxidation von Lipiden, Proteinen und DNA f{\"u}hrt. Obwohl auch oxidierte Lipide und Proteine mit steigendem Alter akkumulieren k{\"o}nnen, f{\"u}hren nur DNA-Oxidationen zu ver{\"a}nderter genomischer Information. Ein m{\"o}glicher Signalweg f{\"u}r gesteigerte ROS-Produktion ist die Aktivierung des Enzyms NADPH-Oxidase (NOX) und die damit verbundene Generierung von ROS durch viele endogene und exogene Substanzen. p47phox ist ein cytosolisches Protein, das eine wichtige Rolle bei der NOX-Aktivierung spielt. Angiotensin II (Ang II) ist ein Beispiel f{\"u}r eine endogene Verbindung, die {\"u}ber NOX-Aktivierung ROS produziert. Rosuvastatin ist ein Arzneistoff mit antioxidativen Eigenschaften (Hochregulation endogener Antioxidantien). Es geh{\"o}rt zur Gruppe der Cholesterinsenker und reduziert ausserdem erh{\"o}htes Auftreten des Angiotensin-II-Typ-1-Rezeptors (AT1R). Normalerweise ist oxidativer Stress im Alter und bei Alterskrankheiten (z. B. Parkinson-Krankheit) erh{\"o}ht. Das Ziel der vorliegenden Arbeit war, mit Hilfe unterschiedlicher Modelle in vitro und in vivo die Rolle von DNA-Schaden durch NOX-vermittelte ROS zu untersuchen und den Einfluss von ROS auf den Alterungsprozess und auf Alterskrankheiten zu bestimmen.},
  subject      = {Oxidativer Stress},
  language  = {en}
}
@phdthesis{Frey2011,
  author    = {Frey, Monika},
  title     = {Effects and mechanisms of a putative human pheromone},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-72292},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {There is evidence that pheromones are communicative signals in animals. However, the existence and function of human pheromones are still under discussion. During the last years several substances have been labeled as putative human pheromones and especially 4,16-androstadien-3-one (androstadienone), found in male and female sweat, became subject of intense investigation. In contrast to common odors androstadienone presumably modulates human physiological and psychological reactions. Data suggest that androstadienone might influence the processing of visual cues, specifically faces or affective stimuli, via projections from the fusiform gyrus and the amygdala. Moreover, attentional processes may be modulated, which is supported by explicit and implicit behavioral data. This thesis includes three experimental studies examining effects of androstadienone exposure on behavioral and cortical reactions to visual and emotional stimuli. The main hypotheses were that androstadienone might influence human behavior to and perception of visual cues. The first study sought to clarify androstadienone effects on attention-related reactions as well as on behavioral tendencies. Motoric approach-avoidance reactions in response to happy and angry facial expressions were investigated in 30 women and 32 men. Participants either inhaled androstadienone or a control solution, without knowing the real content, while performing the following task: they had to push away or to pull towards them a joystick as fast as possible in reaction to either an angry or a happy cartoon face, which was presented on a computer screen. Results showed that androstadienone modulated the participant´s task performance by accelerating the reaction speed compared to the control compound. Faster reactions were observed particularly when reacting to angry faces but not when reacting to happy faces. This might be explained by the finding that human body odors, the source of androstadienone, were found to activate the human fear system, i.e. modulating fear-related attentional processes. Therefore, the quicker reaction towards angry faces with exposure to androstadienone could be due to an enhanced allocation of attentional resources towards fear-related cues like angry faces. Results also showed that androstadienone enhanced men´s approach tendency towards faces independent of emotional expressions. This observation might be explained by androstadienone´s former shown ability to improve attractiveness ratings of other persons. In this regard, the endogenous odor might enhance evaluations of faces in men and, thus, might improve their willingness to approach social stimuli. In contrast to men, women already showed in the control condition higher approach tendency towards faces. Therefore, androstadienone might rather maintain than enhance the approach score in women. In the second study event-related brain potentials (ERPs) triggered by social and non-social visual stimuli were investigated by means of electroencephalography. In a double-blind between-subjects design 51 women participated. Twenty-eight women inhaled androstadienone, whereas 23 women inhaled a control solution. Four different picture categories, i.e. real faces, pictures with couples, pictures with social and non-social scenes, each including three different valence categories, i.e. positive, negative and neutral, should clarify the stimulus type or context androstadienone is acting on. The androstadienone compared to the control odor did not influence brain responses significantly. Explorative analyses, however, suggested that androstadienone influences the processing of faces. While in the control group angry faces elicited larger P300 amplitudes than happy faces, the androstadienone group showed similar P300 amplitudes concerning all emotional expressions. This observation tentatively indicates that the endogenous odor might indeed affect the neuronal responses to emotional facial stimuli, especially late components reflecting evaluative processes. However, this observation has to be verified and further investigated, in particular whether androstadienone caused reduced responses to angry faces or enhanced responses to happy faces. The third study investigated androstadienone effects on face processing especially in men. ERPs elicited by happy, angry and neutral cartoon faces, which were presented on a computer screen, were measured while 16 men, not knowing the applicated odor, inhaled either androstadienone or a control solution. Exposure to androstadienone significantly increased later neuronal responses, the P300 amplitude. This belated component of the ERP reflects attention allocation and evaluative processes towards important stimuli. Therefore, androstadienone might facilitate central nervous face processing by enhancing attention towards these stimuli. In sum, the current results corroborate the notion of androstadienone as an active social chemosignal. In minute amounts and not detectable as an odor it influenced cortical and motoric reactions. Therefore, it might be concluded that androstadienone indeed affects cognitive functions like attentional processes and in turn affects our behavior. The current results further support the notion that androstadienone acts like a human modulator pheromone, namely modulating ongoing behavior or a psychological reaction to a particular context, changing stimulus sensitivity, salience and sensory-motor integration. However, these conclusions remain tentative until further replication takes place, best in ecologically valid environments. Furthermore, one has to keep in mind that the current studies could not replicate several previous findings and could not verify some hypotheses assuming communicative effects of androstadienone. Thus, the main assumption of this thesis that androstadienone is an active chemosignal is still challenged. Also, whether the term "pheromone" is indeed suitable to label androstadienone remains open.},
  subject      = {Pheromon},
  language  = {en}
}
@phdthesis{Deb2011,
  author    = {Deb, Jolly},
  title     = {Role of Transcription Factor NFATc1 in Development, Survival and Function of B Lymphocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57050},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Die Transkriptionsfaktoren der NFAT-Proteinfamilie (Nuclear Factor of Activated T cells, NFATc1-4) sind an entscheidender Stelle in die Regulation des Zellzyklus, des programmierten Zelltodes und der Kanzerogenese involviert. NFATc1 nimmt innerhalb dieser Familie eine Sonderrolle ein, da dessen Aktivit{\"a}t auch durch eine stark induzierbare Expression gesteigert werden kann. Dies ist insbesondere f{\"u}r die Differenzierung und Funktion von T- und B-Lymphozyten von Bedeutung. Weiterhin ist NFATc1 f{\"u}r die Muskel- oder Herzentwicklung notwendig. Eine Reihe von Arbeiten belegen dar{\"u}ber hinaus eine Beteiligung dieses Transkriptionsfaktors an der Entstehung von Leuk{\"a}mien und Lymphomen. W{\"a}hrend klassische Hodgkin-Lymphome allerdings durch eine abgeschaltete NFATc1-Expression gekennzeichnet sind, wird f{\"u}r T-ALL (Akute Lymphatische Leuk{\"a}mie der T-Zelle) eine {\"U}berexpression beschrieben. Die Kernlokalisation dieses Transkriptionsfaktors erfolgt nach Dephosphorylierung des zytoplasmatischen Proteins durch die Phosphatase Calcineurin. Deren Phosphataseaktivit{\"a}t wird durch einen Anstieg des intrazellul{\"a}ren Ca++-Spiegels aktiviert. Inwiefern die Calcineurin-abh{\"a}ngige Kerntranslokalisation den einzigen Aktivierungsmechanismus f{\"u}r NFAT-Faktoren darstellt, ist noch nicht eindeutig gekl{\"a}rt. Nach optimaler Aktivierung von T- bzw. B-Zellen ist die kurze, induzierbare Isoform NFATc1/A das Hauptprodukt des NFATc1-Gens. In dieser Arbeit wurden f{\"u}r die gezielte Deletion des NFATc1-Gens in der Maus zwei verschiedene konditionelle Systeme verwandt. Hierzu wurden Tiere, die ein mit „flox"-Sequenzen versehenes drittes Exon des NFATc1-Gens in der Keimbahn tragen, mit verschiedenen Cre-Rekombinase expremierenden Linien verkreuzt. Der Verlust funktionellen NFATc1-Proteins erfolgt dann fr{\"u}h in der B-Zell-Differenzierung im Knochenmark (Cd79a/mb-1-cre x Nfatc1flx/fl) bzw. in reifen B-Zellen (Cd23-cre x Nfatc1flx/flx). W{\"a}hrend in keiner dieser Linien signifikante Defekte in der Differenzierung "konventioneller B2" B-Lymphozyten beobachtet wurden, hatte die fr{\"u}he Inaktivierung des NFATc1-Gens im Knochenmark den Verlust der B1a-Zell-Population im Peritoneum zur Folge. In vitro zeigten NFATc1-/--B-Zellen aus der Milz nach Aktivierung {\"u}ber den B-Zell-Rezeptor deutliche Defekte in der Zellteilung bei einer gleichzeitigen Zunahme des aktivierungsinduzierten Zelltodes (AICD, activation induced cell death). Die vergleichende Transkriptomanalyse identifizierte wichtige Gene des Ca++/Calcineurin-Signalweges als NFATc1-Zielgene und mitverantwortlich f{\"u}r die Proliferationsdefekte. In NFATc1-defizienten B-Zellen konnte Re-Expression von NFATc1 in geringer Konzentration den aktivierten Zelltod inhibieren, wohingegen hohe Konzentrationen diesen noch weiter f{\"o}rderten. Zusammengenommen l{\"a}sst sich daher schließen, dass NFATc1 entscheidend an der Kontrolle von Proliferation und Zelltod peripherer B-Lymphozyten beteiligt ist. Eine weitere wichtige Funktion kommt NFATc1 beim Klassenwechsel im Immunglobulin-Lokus zu. In den untersuchten M{\"a}usen war die IgG3-Produktion nach Immunisierung mit NP-Ficoll (einem T-Zell-unabh{\"a}ngigen Antigen des Typs II) deutlich reduziert, wenn das NFATc1-Gen in den B-Lymphozyten funktionslos war. Auch die Bildung von IgG3+-Plasmablasten war gehemmt. Zu {\"a}hnlichen Ergebnissen f{\"u}hrten Untersuchungen an isolierten B-Lymphozyten in einem in vitro Klassenwechsel-Modell. Demgegen{\"u}ber zeigten Immunisierungen der Tiere mit NP-KLH (einem T-Zell-abh{\"a}ngigen Antigen) keine signifikanten Abweichungen im Klassenwechsel. Zusammengefasst zeigen diese Daten die große Bedeutung des Transkriptionsfaktors NFATc1 f{\"u}r das {\"U}berleben und die Funktion peripherer B-Lymphozyten.},
  subject      = {NFATc1},
  language  = {en}
}
@phdthesis{Polzien2011,
  author    = {Polzien, Lisa},
  title     = {BAD Phosphorylation: A Novel Link between Apoptosis and Cancer},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-56919},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {BAD (Bcl-2 antagonist of cell death, Bcl-2 associated death promoter) is a pro-apoptotic member of the Bcl-2 protein family that is regulated by phosphorylation in response to survival factors. Although much attention has been devoted to the identification of phosphorylation sites in murine BAD (mBAD), little data are available with respect to phosphorylation of human BAD (hBAD) protein. In this work, we investigated the quantitative contribution of BAD targeting kinases in phosphorylating serines 75, 99 and 118 of hBAD (Chapter 3.1). Our results indicate that RAF kinases phosphorylate hBAD in vivo at these established serine residues. RAF-induced phosphorylation of hBAD was not prevented by MEK inhibitors but could be reduced to control levels by use of the RAF inhibitor Sorafenib (BAY 43-9006). Consistently, expression of active RAF suppressed apoptosis induced by hBAD and the inhibition of colony formation caused by hBAD could be prevented by RAF. In addition, using surface plasmon resonance technique we analyzed the direct consequences of hBAD phosphorylation by RAF with respect to complex formation of BAD with 14-3-3 proteins and Bcl-XL. Phosphorylation of hBAD by active RAF promotes 14-3-3 protein association, whereby the phosphoserine 99 represents the major binding site. Furthermore, we demonstrate in this work that hBAD forms channels in planar bilayer membranes in vitro. This pore-forming capacity is dependent on phosphorylation status and interaction with 14-3-3 proteins. Additionally, we show that hBAD pores possess a funnel-shaped geometry that can be entered by ions and non-charged molecules up to 200 Da (Chapter 3.2). Since both lipid binding domains of hBAD (LBD1 and LBD2) are located within the C-terminal region, we investigated this part of the protein with respect to its structural properties (Chapter 3.3). Our results demonstrate that the C-terminus of hBAD possesses an ordered β-sheet structure in aqueous solution that adopts helical disposition upon interaction with lipid membranes. Additionally, we show that the interaction of the C-terminal segment of hBAD with the BH3 domain results in the formation of permanently open pores, whereby the phosphorylation of serine 118 proved to be necessary for effective pore-formation. In contrast, phosphorylation of serine 99 in combination with 14-3-3 association suppresses formation of channels. These results indicate that the C-terminal part of hBAD controls hBAD function by structural transitions, lipid binding and phosphorylation. Using mass spectrometry we identified in this work, besides the established in vivo phosphorylation sites at serines 75, 99 and 118, several novel hBAD phosphorylation sites (serines 25, 32/34, 97, 124 and 134, Chapter 3.1). To further analyze the regulation of hBAD function, we investigated the role of these newly identified phosphorylation sites on BAD-mediated apoptosis. We found that in contrast to the N-terminal phosphorylation sites, the C-terminal serines 124 and 134 act in an anti-apoptotic manner (Chapter 3.4). Our results further indicate that RAF kinases and PAK1 effectively phosphorylate BAD at serine 134. Notably, in the presence of wild type hBAD, co-expression of survival kinases, such as RAF and PAK1, leads to a strongly increased proliferation, whereas substitution of serine 134 by alanine abolishes this process. Furthermore, we identified hBAD serine 134 to be strongly involved in survival signaling in B-RAF-V600E containing tumor cells and found phosphorylation of this residue to be crucial for efficient proliferation in these cells. Collectively, our findings provide new insights into the regulation of hBAD function by phosphorylation and its role in cancer signaling.},
  subject      = {Krebs <Medizin>},
  language  = {en}
}
@phdthesis{Halder2011,
  author    = {Halder, Partho},
  title     = {Identification and characterization of synaptic proteins of Drosophila melanogaster using monoclonal antibodies of the Wuerzburg Hybridoma Library},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67325},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {For a large fraction of the proteins expressed in the human brain only the primary structure is known from the genome project. Proteins conserved in evolution can be studied in genetic models such as Drosophila. In this doctoral thesis monoclonal antibodies (mAbs) from the Wuerzburg Hybridoma library are produced and characterized with the aim to identify the target antigen. The mAb ab52 was found to be an IgM which recognized a cytosolic protein of Mr ~110 kDa on Western blots. The antigen was resolved by two-dimensional gel electrophoresis (2DE) as a single distinct spot. Mass spectrometric analysis of this spot revealed EPS-15 (epidermal growth factor receptor pathway substrate clone 15) to be a strong candidate. Another mAb from the library, aa2, was already found to recognize EPS-15, and comparison of the signal of both mAbs on Western blots of 1D and 2D electrophoretic separations revealed similar patterns, hence indicating that both antigens could represent the same protein. Finally absence of the wild-type signal in homozygous Eps15 mutants in a Western blot with ab52 confirmed the ab52 antigen to be EPS-15. Thus both the mAbs aa2 and ab52 recognize the Drosophila homologue of EPS-15. The mAb aa2, being an IgG, is more suitable for applications like immunoprecipitation (IP). It has already been submitted to the Developmental Studies Hybridoma Bank (DSHB) to be easily available for the entire research community. The mAb na21 was also found to be an IgM. It recognizes a membrane associated antigen of Mr ~10 kDa on Western blots. Due to the membrane associated nature of the protein, it was not possible to resolve it by 2DE and due to the IgM nature of the mAb it was not possible to enrich the antigen by IP. Preliminary attempts to biochemically purify the endogenously expressed protein from the tissue, gave promising results but could not be completed due to lack of time. Thus biochemical purification of the protein seems possible in order to facilitate its identification by mass spectrometry. Several other mAbs were studied for their staining pattern on cryosections and whole mounts of Drosophila brains. However, many of these mAbs stained very few structures in the brain, which indicated that only a very limited amount of protein would be available as starting material. Because these antibodies did not produce signals on Western blots, which made it impossible to enrich the antigens by electrophoretic methods, we did not attempt their purification. However, the specific localization of these proteins makes them highly interesting and calls for their further characterization, as they may play a highly specialized role in the development and/or function of the neural circuits they are present in. The purification and identification of such low expression proteins would need novel methods of enrichment of the stained structures.},
  subject      = {Taufliege},
  language  = {en}
}
@phdthesis{Jacobs2011,
  author    = {Jacobs, Graeme Brendon},
  title     = {HIV-1 resistance analyses from therapy-na{\"i}ve patients in South Africa, Tanzania and the characterization of a new HIV-1 subtype C proviral molecular clone},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67319},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {The acquired immunodeficiency syndrome (AIDS) is currently the most infectious disease worldwide. It is caused by the human immunodeficiency virus (HIV). At the moment there are ~33.3 million people infected with HIV. Sub-Saharan Africa, with ~22.5 million people infected accounts for 68\% of the global burden. In most African countries antiretroviral therapy (ART) is administered in limited-resource settings with standardised first- and second-line ART regimens. During this study I analysed the therapy-na{\"i}ve population of Cape Town, South Africa and Mwanza, Tanzania for any resistance associated mutations (RAMs) against protease inhibitors, nucleoside reverse transcriptase inhibitors and non-nucleoside reverse transcriptase inhibitors. My results indicate that HIV-1 subtype C accounts for ~95\% of all circulating strains in Cape Town, South Africa. I could show that ~3.6\% of the patient derived viruses had RAMs, despite patients being therapy-na{\"i}ve. In Mwanza, Tanzania the HIV drug resistance (HIVDR) prevalence in the therapy-na{\"i}ve population was 14.8\% and significantly higher in the older population, >25 years. Therefore, the current WHO transmitted HIVDR (tHIVDR) survey that is solely focused on the transmission of HIVDR and that excludes patients over 25 years of age may result in substantial underestimation of the prevalence of HIVDR in the therapy-na{\"i}ve population. Based on the prevalence rates of tHIVDR in the study populations it is recommended that all HIV-1 positive individuals undergo a genotyping resistance test before starting ART. I also characterized vif sequences from HIV-1 infected patients from Cape Town, South Africa as the Vif protein has been shown to counteract the antiretroviral activity of the cellular APOBEC3G/F cytidine deaminases. There is no selective pressure on the HIV-1 Vif protein from current ART regimens and vif sequences was used as an evolutionary control. As the majority of phenotypic resistance assays are still based on HIV-1 subtype B, I wanted to design an infectious HIV-1 subtype C proviral molecular clone that can be used for in vitro assays based on circulating strains in South Africa. Therefore, I characterized an early primary HIV-1 subtype C isolate from Cape Town, South Africa and created a new infectious subtype C proviral molecular clone (pZAC). The new pZAC virus has a significantly higher transient viral titer after transfection and replication rate than the previously published HIV-1 subtype C virus from Botswana. The optimized proviral molecular clone, pZAC could be used in future cell culture and phenotypic HIV resistance assays regarding HIV-1 subtype C.},
  subject      = {HIV},
  language  = {en}
}
@phdthesis{Beisser2011,
  author    = {Beisser, Daniela},
  title     = {Integrated functional analysis of biological networks},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70150},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {In recent years high-throughput experiments provided a vast amount of data from all areas of molecular biology, including genomics, transcriptomics, proteomics and metabolomics. Its analysis using bioinformatics methods has developed accordingly, towards a systematic approach to understand how genes and their resulting proteins give rise to biological form and function. They interact with each other and with other molecules in highly complex structures, which are explored in network biology. The in-depth knowledge of genes and proteins obtained from high-throughput experiments can be complemented by the architecture of molecular networks to gain a deeper understanding of biological processes. This thesis provides methods and statistical analyses for the integration of molecular data into biological networks and the identification of functional modules, as well as its application to distinct biological data. The integrated network approach is implemented as a software package, termed BioNet, for the statistical language R. The package includes the statistics for the integration of transcriptomic and functional data with biological networks, the scoring of nodes and edges of these networks as well as methods for subnetwork search and visualisation. The exact algorithm is extensively tested in a simulation study and outperforms existing heuristic methods for the calculation of this NP-hard problem in accuracy and robustness. The variability of the resulting solutions is assessed on perturbed data, mimicking random or biased factors that obscure the biological signal, generated for the integrated data and the network. An optimal, robust module can be calculated using a consensus approach, based on a resampling method. It summarizes optimally an ensemble of solutions in a robust consensus module with the estimated variability indicated by confidence values for the nodes and edges. The approach is subsequently applied to two gene expression data sets. The first application analyses gene expression data for acute lymphoblastic leukaemia (ALL) and differences between the subgroups with and without an oncogenic BCR/ABL gene fusion. In a second application gene expression and survival data from diffuse large B-cell lymphomas are examined. The identified modules include and extend already existing gene lists and signatures by further significant genes and their interactions. The most important novelty is that these genes are determined and visualised in the context of their interactions as a functional module and not as a list of independent and unrelated transcripts. In a third application the integrative network approach is used to trace changes in tardigrade metabolism to identify pathways responsible for their extreme resistance to environmental changes and endurance in an inactive tun state. For the first time a metabolic network approach is proposed to detect shifts in metabolic pathways, integrating transcriptome and metabolite data. Concluding, the presented integrated network approach is an adequate technique to unite high-throughput experimental data for single molecules and their intermolecular dependencies. It is flexible to apply on diverse data, ranging from gene expression changes over metabolite abundances to protein modifications in a combination with a suitable molecular network. The exact algorithm is accurate and robust in comparison to heuristic approaches and delivers an optimal, robust solution in form of a consensus module with confidence values. By the integration of diverse sources of information and a simultaneous inspection of a molecular event from different points of view, new and exhaustive insights into biological processes can be acquired.},
  subject      = {Bioinformatik},
  language  = {en}
}
@phdthesis{Joseph2011,
  author    = {Joseph, Julie},
  title     = {Studying the role of Th17 cells in autoimmune diabetes and generation of a beta cell reporter mouse by lentiviral transgenesis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-66571},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Type 1 diabetes affects around 0.5\% of the population in developed countries and the incidence rates have been rising over the years. The destruction of beta cells is irreversible and the current therapy available to patients only manages the symptoms and does not prevent the associated pathological manifestations. The patients need lifelong therapy and intensive research is being carried out to identify ways to eliminate autoimmune responses directed against pancreatic beta cells and to replace or regenerate beta cells. The work presented herein aimed at analyzing the role of the Th17 T cell subset, characterized by secretion of the pro- inflammatory cytokine IL-17A, in autoimmune diabetes and also at generating a beta cell reporter mouse line in the NOD background, the most widely- used mouse model for type 1 diabetes. We generated IL- 17A knockdown (KD) NOD mice, using RNAi in combination with lentiviral transgenesis. We analyzed diabetes frequency in IL-17A deficient mice and found that the loss of IL-17A did not protect the transgenic mice from diabetes. Based on these observations, we believe that Th17 cells do not play a critical role in type 1 diabetes through the IL-17A pathway, though they might still be involved in the disease process through alternate pathways. We also generated NOD and NOD-SCID mice with a transgene that drives the beta cell specific expression of a luciferase reporter gene. We used a lentiviral construct, which combined a luciferase sequence and a short- hairpin RNA (shRNA) expression cassette, allowing gene- knockdown under the beta cell specific rat insulin promoter (RIP). These mice will be of use in studying beta cell phenotypes resulting from the knockdown of target genes, using non- invasive bioimaging. We believe that the generation of these reporter mouse lines for diabetes studies will prove valuable in future investigations. Furthermore, the demonstration that the loss of IL-17A does not alter susceptibility to type 1 diabetes should help clarify the controversial involvement of Th17 cells in this disease.},
  subject      = {Diabetes mellitus},
  language  = {en}
}