@phdthesis{Ribbeck2022, author = {Ribbeck, Tatjana}, title = {Seltenerdmetallkomplexe mit Cyanoborat-Anionen - sowie - Synthese und Charakterisierung des Hydroxytricyanoborat-Anions}, doi = {10.25972/OPUS-18346}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183465}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Im Rahmen dieser Arbeit konnten Seltenerdmetallcyanoborate mit unterschiedlich funktionalisierten Anionen, beispielsweise Hydrido-, Fluoro- oder Perfluoralkylcyanoborat-Anionen, synthetisiert und vollst{\"a}ndig charakterisiert werden. L{\"o}sungen der wasserfreien Komplexe Ln[BH2(CN)2]3 (Ln = La, Eu, Ho) in der korrespondierenden ionischen Fl{\"u}ssigkeit [EMIm][BH2(CN)2] konnten hinsichtlich Dichte Viskosit{\"a}t und Leitf{\"a}higkeit in Abh{\"a}ngigkeit der Konzentration des gel{\"o}sten Komplexes untersucht werden. Alle Europiumkomplexe wurden hinsichtlich ihrer photochemischen Eigenschaften untersucht. Weiterhin konnte im Rahmen dieser Arbeit die erste selektive Synthese des Hydroxytricyanoborat-Anions [B(OH)(CN)3]- vorgestellt werden. Ausgehend von der Br{\o}nsteds{\"a}ure dieses Anions konnte die Synthese einer ganzen Reihe von Salzen und Komplexverbindungen, sowie von ionischen Fl{\"u}ssigkeiten mit diesem Anion realisiert werden.}, subject = {Cyanoborate}, language = {de} } @phdthesis{Kasaragod2022, author = {Kasaragod, Vikram Babu}, title = {Biochemical and Structural Basis for the Moonlighting Function of Gephyrin}, doi = {10.25972/OPUS-14307}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143077}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Neurons are specialized cells dedicated to transmit the nerve impulses throughout the human body across specialized structures called synapses. At the synaptic terminals, a crosstalk between multiple macromolecules regulates the structure and function of the presynaptic nerve endings and the postsynaptic recipient sites. Gephyrin is the central organizer at inhibitory postsynaptic specializations and plays a crucial role in the organization of these structures by anchoring GABAA receptors (GABAAR) and glycine receptors (GlyR) to the postsynaptic membrane. This 93 kDa protein features an N-terminal G domain and a C-terminal E domain and the latter interacts directly with the intracellular loop between transmembrane helices 3 and 4 of certain subunits of the GlyRs and GABAARs. Biochemical and structural analyses have already provided valuable insights into the gephyrin-GlyR interaction. Interestingly, biochemical studies on the gephyrin-GABAAR interaction demonstrated that the GABAARs also depend on the same binding site as the GlyRs for the interaction with the gephyrin, but the molecular basis for this receptor specific interaction of gephyrin was still unknown. Co-crystal structures of GephE-GABAAR α3- derived peptides with supporting biochemical data presented in this study deciphered the receptor-specific interactions of gephyrin in atomic detail. In its moonlighting function, gephyrin also catalyzes the terminal step of the evolutionarily conserved molybdenum cofactor biosynthesis. Molybdenum, an essential transition element has to be complexed with a pterin-based cofactor resulting in the formation of the molybdenum cofactor (Moco). Moco is an essential component at the active site of all molybdenum-containing enzymes with the exception of nitrogenase. Mutations in enzymes involved in this pathway lead to a rare yet severe disease called Moco deficiency, which manifest itself in severe neurodevelopmental abnormalities and early childhood death. Moco biosynthesis follows a complex multistep pathway, where in the penultimate step, the N-terminal G domain of gephyrin activates the molybdopterin to form an adenylated molybdopterin intermediate. In the terminal step, this intermediate is then transferred to the C-terminal E domain of gephyrin, which catalyzes the metal insertion and deadenylation reaction to form active Moco. Previous biochemical and structural studies provided valuable insights into the penultimate step of the Moco biosynthesis but the terminal step remained elusive. Through the course of my dissertation, I crystallized the C-terminal E domain in the apo-form as well as in complex with ADP and AMP. These structures shed lightonto the deadenylation reaction and the formation of a ternary E-domain-ADP-Mo/W complex and thus provide structural insight into the metal insertion mechanism. Moreover, the structures also provided molecular insights into a mutation leading to Moco deficiency. Finally, ternary complexes of GephE, ADP and receptor-derived peptides provided first clues regarding the integration of gephyrin's dual functionality. In summary, during the course of the dissertation I was able to derive high resolution structural insights into the interactions between gephyrin and GABAARs, which explain the receptor-specific interaction of gephyrin and, furthermore, these studies can be extended in the future to understand GABAAR subunit-specific interactions of gephyrin. Finally, the understanding of Moco biosynthesis shed light on the molecular basis of the fatal Moco deficiency.}, subject = {Gephyrin}, language = {en} } @phdthesis{Wencker2022, author = {Wencker, Freya Dorothea Ruth}, title = {The methionine biosynthesis operon in \(Staphylococcus\) \(aureus\): Role of concerted RNA decay in transcript stability and T-box riboswitch turnover}, doi = {10.25972/OPUS-20712}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-207124}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Methionine is the first amino acid of every newly synthesised protein. In combination with its role as precursor for the vital methyl-group donor S-adenosylmethionine, methionine is essential for every living cell. The opportunistic human pathogen Staphylococcus aureus is capable of synthesising methionine de novo, when it becomes scarce in the environment. All genes required for the de novo biosynthesis are encoded by the metICFE-mdh operon, except for metX. Expression is controlled by a hierarchical network with a methionyl-tRNA-specific T-box riboswitch (MET-TBRS) as centrepiece, that is also referred to as met leader (RNA). T-box riboswitches (TBRS) are regulatory RNA elements located in the 5'-untranslated region (5'-UTR) of genes. The effector molecule of T-box riboswitches is uncharged cognate tRNA. The prevailing mechanism of action is premature termination of transcription of the nascent RNA in the absence of the effector (i.e. uncharged cognate tRNA) due to formation of a hairpin structure, the Terminator stem. In presence of the effector, a transient stabilisation of the alternative structure, the Antiterminator, enables transcription of the downstream genes ('read-through'). Albeit, after the read-through the thermodynamically more stable Terminator eventually forms. The Terminator and the Antiterminator are two mutually exclusive structures. Previous work of the research group showed that in staphylococci the MET-TBRS ensures strictly methionine-dependent control of met operon expression. Uncharged methionyl-tRNA that activates the system is only present in sufficient amounts under methionine-deprived conditions. In contrast to other bacterial TBRS, the staphylococcal MET-TBRS has some characteristic features regarding its length and predicted secondary structure whose relevance for the function are yet unkown. Aim of the present thesis was to experimentally determine the structure of the met leader RNA and to investigate the stability of the met operon-specific transcripts in the context of methionine biosynthesis control. Furthermore, the yet unknown function of the mdh gene within the met operon was to be determined. In the context of this thesis, the secondary structure of the met leader was determined employing in-line probing. The structural analysis revealed the presence of almost all highly conserved T-box riboswitch structural characteristics. Furthermore, three additional stems, absent in all T-box riboswitches analysed to date, could be identified. Particularly remarkable is the above average length of the Terminator stem which renders it a potential target of the double-strand-specific endoribonuclease III (RNase III). The RNase III-dependent cleavage of the met leader could be experimentally verified by the use of suitable mutants. Moreover, the exact cleavage site within the Terminator was determined. The unusual immediate separation of the met leader from the met operon mRNA via the RNase III cleavage within the Terminator stem induces the rapid degradation of the met leader RNA and, most likely, that of the 5'-region of the met mRNA. The met mRNA is degraded from its 5'-end by the exoribonuclease RNase J. The stability of the met mRNA was found to vary over the length of the transcript with an instable 5'-end (metI and metC) and a longer half-life towards the 3'-end (metE and mdh). The varying transcript stability is reflected by differences in the available cellular protein levels. The obtained data suggest that programmed mRNA degradation is another level of regulation in the complex network of staphylococcal de novo methionine biosynthesis control. In addition, the MET-TBRS was studied with regard to a future use as a drug target for novel antimicrobial agents. To this end, effects of a dysregulated methionine biosynthesis on bacterial growth and survival were investigated in met leader mutants that either caused permanent transcription of the met operon ('ON') or prevented operon transcription ('OFF'), irrespective of the methionine status in the cell. Methionine deprivation turned out to be a strong selection pressure, as 'OFF' mutants acquired adaptive mutations within the met leader to restore met operon expression that subsequently re-enabled growth. The second part of the thesis was dedicated to the characterisation of the Mdh protein that is encoded by the last gene of the met operon and whose function is unknown yet. At first, co-transcription and -expression with the met operon could be demonstrated. Next, the Mdh protein was overexpressed and purified and the crystal structure of Mdh was solved to high resolution by the Kisker research group (Rudolf-Virchow-Zentrum W{\"u}rzburg). Analysis of the structure revealed the amino acid residues crucial for catalytic activity, and zinc was identified as a co-factor of Mdh. Also, Mdh was shown to exist as a dimer. However, identification of the Mdh substrate was, in the context of this thesis, (still) unsuccessful. Nevertheless, interactions of Mdh with enzymes of the met operon could be demonstrated by employing the bacterial two-hybrid system. This fact and the high conservation of mdh/Mdh on nucleotide and amino acid level among numerous staphylococcal species suggests an important role of Mdh within the methionine metabolism that should be a worthwhile subject of future research.}, subject = {Staphylococcus aureus}, language = {en} } @phdthesis{Lisowski2022, author = {Lisowski, Clivia}, title = {Maturation of the \(Salmonella\) containing vacuole is compromised in G1 arrested host cells}, doi = {10.25972/OPUS-18523}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-185239}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The interaction of bacterial pathogens and the human host is a complex process that has shaped both organisms on a molecular, cellular and population level. When pathogenic bacteria infect the human body, a battle ensues between the host immune system and the pathogen. In order to escape an immune response and to colonize the host, pathogenic bacteria have developed diverse virulence strategies and some pathogens even replicate within host cells. For survival and propagation within the dynamic environment of a host cell, these bacteria interfere with the regulation of host pathways, such as the cell cycle, for their own benefit. The intracellular pathogen Salmonella Typhimurium invades eukaryotic cells and resides and replicates in a modified vacuolar compartment in which it is protected from the innate immune response. To this end, it employs a set of virulence factors that help to invade cells (SPI-1 effectors) and to hijack and modify the host endolysosomal system, in order to stabilize and mature its vacuolar niche (SPI-2 effectors). Previous studies have shown that Salmonella arrests host cells in G2/M phase and that Salmonella infected cells progress faster from G1 into S phase, suggesting that the G1 phase is disadvantageous for Salmonella infection. In fact, it has already been observed that Salmonella replication is impaired in G1 arrested cells. However, the reason for this impairment remained unclear. The current study addressed this question for the first time and revealed that the highly adapted, intracellular lifestyle of Salmonella is drastically altered upon G1 arrest of the host cell. It is shown that proteasomal degradation in G1 arrested cells is delayed and endolysosomal and autophagosomal trafficking is compromised. Accordingly, processing of lysosomal proteins is insufficient and lysosomal activity is decreased; resulting in uneven distribution and accumulation of endolysosomes and autophagosomes, containing undegraded cargo. The deregulation of these cellular signaling pathways affects maturation of the Salmonella containing vacuole (SCV). For the first time it is shown that acidification of SCVs is impaired upon G1 arrest. Thus, an important environmental factor for the switch from SPI-1 to SPI-2 gene expression is missing and the SPI-2 system is not activated. Consequently, targeting and modification of host cell structures by SPI-2 effectors e.g. recruitment of endolysosomal membrane proteins, like LAMP1, or exchange of endosomal cargo, is compromised. In addition, degradation of Salmonella SPI-1 effectors by the host proteasome is delayed. Their prolonged presence sustained the recruitment of early endosomes and contributed to the SCV remaining in an early, vulnerable maturation stage. Finally, it was shown that SCV membrane integrity is compromised; the early SCV ruptures and bacteria are released into the cytoplasm. Depending on the host cell type, SPI-2 independent, cytoplasmic replication is promoted. This might favor bacterial spreading, dissemination into the tissue and provide an advantage in host colonization. Overall, the present study establishes a link between host cell cycle regulation and the outcome of Salmonella infection. It fills the gap of knowledge as to why the host cell cycle stage is of critical importance for Salmonella infection and sheds light on a key aspect of host-pathogen interaction.}, subject = {Salmonella Typhimurium}, language = {en} } @phdthesis{Wallstabe2022, author = {Wallstabe, Lars}, title = {Development and preclinical evaluation of tumour-reactive T cells expressing a chemically programmable chimeric antigen receptor}, doi = {10.25972/OPUS-17907}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179071}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The genetic modification of T cells for the expression a chimeric antigen receptor (CAR) endows them with a new specificity for an antigen. Adoptive immunotherapy with CD19-CAR T cells has achieved high rates of sustained complete remissions in B cell malignancies. However, the downregulation or loss of the targeted antigen after mono-specific CAR T cell therapy, e.g. against CD19 or CD22, has been reported. Targeting multiple antigens on tumour cells, sequentially or simultaneously, could overcome this limitation. Additionally, targeting multiple antigens with CAR T cells could drive the translation from hematologic malignancies to prevalent solid cancers, which often express tumour-associated antigens heterogeneously. We hypothesised that expression of a universal CAR, which can be programmed with hapten-like molecules, could endow T cells with specificities for multiple antigens. In this study we introduce a novel chemically programmable CAR (cpCAR) based on monoclonal antibody h38C2. Our data show, that cpCARs form a reversible chemical bond to molecules containing a diketone-group and therefore can be programmed to acquire multiple specificities. We programmed cpCAR T cells with hapten-like compounds against integrins αvβ3 and α4β1 as well as the folate receptor. We observed tumour cell lysis, IFN ɣ and IL-2 production and proliferation of programmed cpCAR T cells against tumour cells expressing the respective target antigen in vitro. As a reference to cpCARs programmed against αvβ3, we further introduced novel conventional αvβ3-CARs. These CARs, based on humanised variants of monoclonal antibody LM609 (hLM609), directly bind to integrin αvβ3 via their scFv. The four αvβ3-CAR constructs comprised either an scFv with higher affinity (hLM609v7) or lower affinity (hLM609v11) against αvβ3 integrin and either a long (IgG4 hinge, CH2, CH3) or short (IgG4 hinge) extracellular spacer. We selected the hLM609v7-CAR with short spacer, which showed potent anti-tumour reactivity both in vitro and in a murine xenograft model, for comparison with the cpCAR programmed against αvβ3. Our data show specific lysis of αvβ3-positive tumour cells, cytokine production and proliferation of both hLM609-CAR T cells and cpCAR T cells in vitro. However, conventional hLM609-CAR T cells mediated stronger anti-tumour effects compared to cpCAR T cells in the same amount of time. In line with the in vitro data, complete destruction of tumour lesions in a murine melanoma xenograft model was only observed for mice treated with conventional αvβ3-CAR T cells. Collectively, we introduce a cpCAR, which can be programmed against multiple tumour antigens, and hLM609-CARs specific for the integrin αvβ3. The cpCAR technology bears the potential to counteract current limitations, e.g. antigen loss, of current monospecific CAR T cell therapy. Targeting αvβ3 integrin with CAR T cells could have clinical applications in the treatment of solid malignancies, because αvβ3 is not only expressed on a variety of solid malignancies, but also on tumour-associated vasculature and fibroblast.}, subject = {Tumorimmunologie}, language = {en} } @phdthesis{Kuehl2022, author = {K{\"u}hl, Julia}, title = {FAAP100, der FA/BRCA-Signalweg f{\"u}r genomische Stabilit{\"a}t und das DNA-Reparatur-Netzwerk}, doi = {10.25972/OPUS-17166}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171669}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die Fanconi-An{\"a}mie (FA) ist eine seltene, heterogene Erbkrankheit. Sie weist ein sehr variables klinisches Erscheinungsbild auf, das sich aus angeborenen Fehlbildungen, h{\"a}matologischen Funktionsst{\"o}rungen, einem erh{\"o}hten Risiko f{\"u}r Tumorentwicklung und endokrinen Pathologien zusammensetzt. Die Erkrankung z{\"a}hlt zu den genomischen Instabilit{\"a}tssyndromen, welche durch eine fehlerhafte DNA-Schadensreparatur gekennzeichnet sind. Bei der FA zeigt sich dies vor allem in einer charakteristischen Hypersensitivit{\"a}t gegen{\"u}ber DNA-quervernetzenden Substanzen (z. B. Mitomycin C, Cisplatin). Der zellul{\"a}re FA-Ph{\"a}notyp zeichnet sich durch eine erh{\"o}hte Chromosomenbr{\"u}chigkeit und einen Zellzyklusarrest in der G2-Phase aus. Diese Charakteristika sind bereits spontan vorhanden und werden durch Induktion mit DNA-quervernetzenden Substanzen verst{\"a}rkt. Der Gendefekt ist dabei in einem der 22 bekannten FA-Gene (FANCA, -B, -C, -D1, -D2, -E, -F, -G, -I, -J, -L, -M, -N, -O, -P, -Q, -R, -S, -T, -U, -V, -W) oder in noch unbekannten FA-Genen zu finden. Die FA-Gendefekte werden mit Ausnahme von FANCR (dominant-negative de novo Mutationen) und FANCB (X-chromosomal) autosomal rezessiv vererbt. Die FA-Genprodukte bilden zusammen mit weiteren Proteinen den FA/BRCA-Signalweg. Das Schl{\"u}sselereignis dieses Signalwegs stellt die Monoubiquitinierung von FANCD2 und FANCI (ID2-Komplex) dar. Ausgehend davon l{\"a}sst sich zwischen upstream- und downstream-gelegenen FA-Proteinen unterscheiden. Letztere sind direkt an der DNA-Schadensreparatur beteiligt. Zu den upstream-gelegenen Proteinen z{\"a}hlt der FA-Kernkomplex, der sich aus bekannten FA-Proteinen und aus FA-assoziierten-Proteinen (FAAPs) zusammensetzt und f{\"u}r die Monoubiquitinierung des ID2-Komplexes verantwortlich ist. F{\"u}r FAAPs wurden bisher keine pathogenen humanen Mutationen beschrieben. Zu diesen Proteinen geh{\"o}rt auch FAAP100, das mit FANCB und FANCL innerhalb des FA-Kernkomplexes den Subkomplex LBP100 bildet. Durch die vorliegende Arbeit wurde eine n{\"a}here Charakterisierung dieses Proteins erreicht. In einer Amnion-Zelllinie konnte eine homozygote Missense-Mutation identifiziert werden. Der Fetus zeigte einen typischen FA-Ph{\"a}notyp und auch seine Zellen wiesen charakteristische FA-Merkmale auf. Der zellul{\"a}re Ph{\"a}notyp ließ sich durch FAAP100WT komplementieren, sodass die Pathogenit{\"a}t der Mutation bewiesen war. Unterst{\"u}tzend dazu wurden mithilfe des CRISPR/Cas9-Systems weitere FAAP100-defiziente Zelllinien generiert. Diese zeigten ebenfalls einen typischen FA-Ph{\"a}notyp, welcher sich durch FAAP100WT komplementieren ließ. Die in vitro-Modelle dienten als Grundlage daf{\"u}r, die Funktion des FA-Kernkomplexes im Allgemeinen und die des Subkomplexes LBP100 im Besonderen besser zu verstehen. Dabei kann nur durch intaktes FAAP100 das LBP100-Modul gebildet und dieses an die DNA-Schadensstelle transportiert werden. Dort leistet FAAP100 einen essentiellen Beitrag f{\"u}r den FANCD2-Monoubiquitinierungsprozess und somit f{\"u}r die Aktivierung der FA-abh{\"a}ngigen DNA-Schadensreparatur. Um die Funktion von FAAP100 auch in vivo zu untersuchen, wurde ein Faap100-/--Mausmodell generiert, das einen mit anderen FA-Mausmodellen vergleichbaren, relativ schweren FA-Ph{\"a}notyp aufwies. Aufgrund der Ergebnisse l{\"a}sst sich FAAP100 als neues FA-Gen klassifizieren. Zudem wurde die Rolle des Subkomplexes LBP100 innerhalb des FA-Kernkomplexes weiter aufgekl{\"a}rt. Beides tr{\"a}gt zu einem besseren Verst{\"a}ndnis des FA/BRCA-Signalweges bei. Ein weiterer Teil der vorliegenden Arbeit besch{\"a}ftigt sich mit der Charakterisierung von FAAP100138, einer bisher nicht validierten Isoform von FAAP100. Durch dieses Protein konnte der zellul{\"a}re FA-Ph{\"a}notyp von FAAP100-defizienten Zelllinien nicht komplementiert werden, jedoch wurden Hinweise auf einen dominant-negativen Effekt von FAAP100138 auf den FA/BRCA-Signalweg gefunden. Dies k{\"o}nnte zu der Erkl{\"a}rung beitragen, warum und wie der Signalweg, beispielsweise in bestimmtem Gewebearten, herunterreguliert wird. Zudem w{\"a}re eine Verwendung in der Krebstherapie denkbar.}, subject = {Fanconi-An{\"a}mie}, language = {de} } @phdthesis{Chen2022, author = {Chen, Mengjia}, title = {Right Ventricular Dysfunction contributes to Left Ventricular Thrombus Formation in Patients post Anterior Myocardial Infarction}, doi = {10.25972/OPUS-20414}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204149}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Our current data demonstrate that besides the known risk factors, including apical aneurysm, reduced left ventricular longitudinal systolic function (MAPSE) and advanced diastolic dysfunction, Right ventricular dysfunction as determined by reduced tricuspid annular plane systolic excursion (TAPSE) or right ventricular fractional area change (RV_FAC) is independently associated with left ventricular thrombus formation in acute anterior myocardial infarction patients, especially in the setting of anterior myocardial infarction without the formation of an apical aneurysm. This study suggests that besides left ventricular abnormalities, right ventricular dysfunction likewise contributes LVT formation in patients with acute anterior myocardial infarction.}, subject = {Thrombus}, language = {en} } @phdthesis{Seifert2022, author = {Seifert, Franziska Katharina}, title = {Kollagen-Crosslinking der Hornhaut mit UV-A und Riboflavin zur Behandlung des Keratokonus - 10-Jahres-Ergebnisse}, doi = {10.25972/OPUS-21457}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214571}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Ziel der Studie: Evaluation der Effektivit{\"a}t und Sicherheit des Kollagen-Crosslinkings der Hornhaut mit Riboflavin und UV-A (CXL) bei progressivem Keratokonus {\"u}ber einen Nachbeobachtungszeitraum von bis zu 10 Jahren. Design: Retrospektive klinische L{\"a}ngsschnittstudie Methoden: 131 Augen von 131 Patienten (m{\"a}nnlich:weiblich = 95:36) erhielten an der Universit{\"a}ts-Augenklinik W{\"u}rzburg zwischen 2006 und 2016 ein Kollagen-Crosslinking (CXL) nach dem Dresdner Standardprotokoll, bestehend aus einer Abrasio, Applikation von iso-osmolaren Riboflavin/Dextran-Augentropfen f{\"u}r 30 min und anschließender UV-A-Bestrahlung mit 3 mW/cm2 f{\"u}r 30 min. Die retrospektive Nachbeobachtung betrug 1 (n=103 Augen) bis maximal 10 Jahre (n=44 Augen). Einschlusskriterien waren eine Zunahme des maximalen Hornhautkr{\"u}mmungsradius (Kmax, gemessen mittels Pentacam HR) >1 dpt und eine Hornhautdicke >400 µm nach Abrasio. F{\"u}r parametrische bzw. nichtparametrische Daten wurde der T-Test bzw. der Wilcoxon-Vorzeichen-Rangsummentest durchgef{\"u}hrt. Ergebnisse: 1 bis 3 Jahre pr{\"a}operativ nahm der Median von Kmax und K2 signifikant um 1,5 dpt (p=0,001) und 1,1 dpt (p<0,001) bis zur Behandlung zu. Die apikale Hornhautdicke nahm nach 1-3 Jahren pr{\"a}operativ um 12 µm ab (p=0,003). Postoperativ stieg der Median von K2 zun{\"a}chst bis nach 1 Jahr um 0,1 dpt, nahm dann aber {\"u}ber den weiteren Nachbeobachtungszeitraum kontinuierlich ab, nach 10 Jahren lag er um 0,85 dpt (p=0,021) unter dem Ausgangswert. Die mittlere apikale Hornhautdicke nahm nach 3, 7 bzw. 10 Jahren um 11 µm (p<0,001), 9 µm (p=0,014) und 3 µm (p=0,358) ab. Der mediane Kmax zeigte Schwankungen ohne signifikante Ver{\"a}nderung. Der mittlere bestkorrigierte Visus (logMAR) nahm nach 5 Jahren signifikant um 0,13 und nach 10 Jahren um 0,08 ab (p=0,013 und p=0,010). Der Anteil der Non-Responder, definiert durch einen postoperativen Anstieg von Kmax>2 dpt, nahm von 16\% nach 5 auf 33\% nach 10 Jahren zu. Risikofaktoren waren ein junges Alter, hoher Astigmatismus, eine d{\"u}nne Hornhaut und atopische Dermatitis. 4 Augen erhielten im Verlauf komplikationslos eine Revernetzung, woraufhin sich keine weitere Krankheitsprogression zeigte. Fazit: Die CXL-Behandlung kann die Progression des Keratokonus verlangsamen oder stoppen. Allerdings war ab 5 Jahren nach dem Eingriff eine Abnahme des Anteils der Responder zu beobachten. Regelm{\"a}ßige Nachkontrollen sollten daher besonders auch im Langzeitverlauf durchgef{\"u}hrt werden, um eine erneute Progression fr{\"u}hzeitig erkennen und behandeln zu k{\"o}nnen.}, subject = {Keratokonus}, language = {de} } @phdthesis{Haering2022, author = {H{\"a}ring, Mathias}, title = {Neuartige Tricyanoborate der Tetrelgruppe -und- Poly- und Ionomere mit Tricyanoboraten}, doi = {10.25972/OPUS-16948}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169488}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Diese Arbeit besch{\"a}fftig sich mit der Synthese und Charakterisierung neuartiger Tricyanoborate der Hauptgruppe 4, sowie der Synthese und Charakterisierung neuartiger Polymere mit Tricyanoboratgruppen.}, subject = {Tricyanoborate}, language = {de} } @phdthesis{Heib2022, author = {Heib, Tobias}, title = {The role of Rho GTPases in megakaryopoiesis and thrombopoiesis}, doi = {10.25972/OPUS-21664}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-216645}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Platelets, derived from megakaryocytes (MKs) in the bone marrow (BM), are small, anucleated cells that circulate in the bloodstream and are critical for thrombosis and hemostasis. Megakaryo- and subsequent thrombopoiesis are highly orchestrated processes involving the differentiation and maturation of MKs from hematopoietic stem cells (HSCs), after which MKs are able to release platelets into the bloodstream, a process termed proplatelet formation (PPF). Here, the MK penetrates the endothelial lining and releases cytoplasmic portions (proplatelets) into the blood stream, which finally mature into platelets within the ciruculation. PPF requires an extensive crosstalk as well as a tight regulation of the MK cytoskeleton, in which small GTPases of the Rho family, such as RhoA and Cdc42 are critically involved and play opposing roles. MK and platelet specific Cdc42 or RhoA-deficiency in mice results in macrothrombocytopenia. Moreover, RhoA deficient mice displayed a frequent mislocalization of entire MKs into BM sinusoids, a finding that was reverted upon concomitant lack of Cdc42 but accompanied by an aggravated macrothrombocytopenia. Whether receptors are involved in the process of transendothelial MK migration, however, remained unclear. In the first part of this thesis, a centrifugation-based method ('spin isolation') to harvest murine BM cells was established, which not only reduces experimental time, costs and animals but is also highly suitable for studies on primary and in vitro cultured BM-derived cells. The spin isolation was used particularly for MK studies during the course of the thesis. In the second part of this thesis, a MK- and platelet-specific RhoA/Cdc42 double-deficiency was shown to result in reduced expression of a variety of MK-specific glycoproteins and cytoskeletal regulators of importance during MK maturation and PPF, a phenotype culminating in virtually abolished platelet biogenesis. We thus uncovered that RhoA/Cdc42-regulated gene expression is a prerequisite for cytoplasmic MK maturation, but dispensable for endomitosis. In the third part of this thesis we analyzed mice double-deficient in RhoA and prominent MK receptors which are potentially involved in the regulation of PPF in the BM environment. We were able to show that integrins as well as the inhibitory receptor G6b-B are dispensable for transendothelial migration of RhoA-deficient MKs. Surprisingly however, the myelofibrosis and concomitant osteosclerosis observed in G6b-B single-deficient mice was attenuated in RhoA/G6b B double-deficient mice, thus implying an important role of RhoA during myelofibrotic disease progression. BM transplantation experiments furthermore revealed that not only the macrothrombocytopenia but also the transmigration of RhoA-deficient MKs is due to cell-intrinsic defects and not related to possible Pf4-Cre off-target effects in non-hematopoietic cells. In the last part of this study we demonstrated that the new approach for MK- and platelet-specific gene ablatation using Gp1ba-Cre deleter mice is associated with intrinsic MK defects and in addition results in insufficient depletion of RhoA compared to the Pf4-Cre model, positioning the latter still as the gold standard for studying MK biology.}, subject = {Megakaryozyt}, language = {en} } @phdthesis{Guentzel2022, author = {G{\"u}ntzel, Paul Mathias}, title = {Bioinspired Ion Pairs Transforming Poorly Water-soluble Compounds into Protic Ionic Liquids and Deep Eutectic Solvents}, doi = {10.25972/OPUS-21980}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219806}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Microbial, mammalian and plant cells produce and contain secondary metabolites, which typically are soluble in water to prevent cell damage by crystallization. The formation of ion pairs, e.g. with carboxylic acids or mineral acids, is a natural blueprint to keep basic metabolites in solution. It was aimed at showing whether the mostly large carboxylates form soluble protic ionic liquids (PILs) with basic natural products resulting in enhanced aqueous solubility. Furthermore, their supramolecular pattern in aqueous solution was studied. Thereby, naturally occurring carboxylic acids were identified being appropriate counterions for natural basic compounds and facilitate the formation of PILs with their beneficial characteristics, like improved dissolution rate and enhanced apparent solubility.}, subject = {Ionic Liquids}, language = {en} } @phdthesis{Ritschel2022, author = {Ritschel, Benedikt Tobias}, title = {Lewis-Basen-stabilisierte Bor-Bor-Mehrfachbindungssysteme - Reaktivit{\"a}tsstudien an Diboracumulenen und Dicyanodiborenen}, doi = {10.25972/OPUS-24330}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-243306}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die vorliegende Arbeit umfasst im Wesentlichen Studien {\"u}ber die Reaktivit{\"a}t von Diboracumulenen sowie Dicyanodiborenen gegen{\"u}ber diversen Substraten verschiedener Substanzklassen, wie z. B. Acetylenen, Aminen, Aziden, Nitrilen, Isonitrilen und {\"U}bergangsmetallen. Auf diese Weise sollen zun{\"a}chst Einblicke in das unterschiedliche Reaktionsverhalten der niedervalenten Borverbindungen erm{\"o}glicht sowie ein Verst{\"a}ndnis f{\"u}r die erhaltenen, teils neuartigen, Bindungsmodi und Substanzklassen etabliert werden. Die jeweiligen MecAAC- und CycAAC-stabilisierten Verbindungen wurden hierbei auf den Einfluss des sterischen Anspruchs der Liganden in Bezug auf die Reaktivit{\"a}t untersucht. Die aufgef{\"u}hrten Kapitel beziehen sich daher auf die Reaktivit{\"a}t der Diboracumulene wie auch die der Dicyanodiborene gegen{\"u}ber Verbindungen jeweils einer bestimmten Substanzklasse. Die erhaltenen Produkte werden, soweit m{\"o}glich, miteinander verglichen.}, subject = {Bor}, language = {de} } @phdthesis{Matler2022, author = {Matler, Alexander}, title = {Synthese und Reaktivit{\"a}t von {\"U}bergangsmetall-stabilisierten und Lewis-basenstabilisierten Borylenen}, doi = {10.25972/OPUS-24018}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-240184}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die vorliegende Arbeit befasst sich im ersten Teil mit der Reaktivit{\"a}t von Gruppe 8 Borylenkomplexen. Zun{\"a}chst wurde der Eisenborylenkomplex 71 mit verschiedenen Carbodiimiden umgesetzt. Die entstandenen Produkte in Form von Spiroverbindungen, [2+2]-Cycloadditionsprodukten sowie Diazadiboretidinen konnten strukturell und spektroskopisch untersucht werden. Außerdem wurde 71 mit Aziden umgesetzt, was NMR-spektroskopisch zur Bildung von Tetrazaborolen f{\"u}hrt. Der Eisenbis(borylen)komplex 72 wurde ebenfalls mit Carbodiimiden umgesetzt und die entstandenen Verbindungen, unter anderem Diazadiboretidine, strukturell und spektroskopisch untersucht. Eine Umsetzung von 72 mit Stickstoffbasen wie Azobenzol, 2,2'-Bipyridin oder Pyridazin f{\"u}hrte bei letzterem zur Bildung eines Koordinationsprodukts. W{\"a}hrend die Umsetzungen des Eisentetrakis(borylen)komplexes 73 mit Methylisocyanid, Magnesium und Trimethylphosphan zu Zersetzung f{\"u}hrten, konnten mit Bis(piperidyl)acetylen und Diisopropylcarbodiimid keine Umsetzungen festgestellt werden. Nach Aufnahme eines UV/Vis- und CV-Spektrums des Eisentetraborkomplexes 74 wurde versucht, diesen mit diversen Erd- und Erdalkalimetallverbindungen zu reduzieren. Hierbei konnte entweder keine Reaktion oder Zersetzung festgestellt werden. Weitere Umsetzungen von 74 erfolgten mit unterschiedlichen Lewis-Basen, Stickstoffbasen, S{\"a}uren, Gasen, Chalkogenen, DIC und einer Platin(0)-verbindung. Diese Umsetzungen f{\"u}hrten zu keinen identifizierbaren Produkten. Im zweiten Teil dieser Arbeit wurde die Synthese und Reaktivit{\"a}t des basenstabilisierten Borylens 89 untersucht. Nach Verbesserung der Synthesebedingungen konnte ein photolytisch induzierter Ligandenaustausch des CO-Liganden mit verschiedenen Substraten durchgef{\"u}hrt werden. Hierbei f{\"u}hrten die Umsetzungen mit Carbenen oder Phosphanen in Abh{\"a}ngigkeit derer sterischer Eigenschaften zu den entsprechenden Adduktverbindungen. Außerdem konnte eine Adduktverbindung mit Schwefel dargestellt werden, w{\"a}hrend eine Umsetzung mit Selen nur zur Zersetzung f{\"u}hrte. Die Umsetzung mit DMAP lieferte im Gegensatz zur den vorherigen Adduktverbindungen ein biradikalisches Produkt, welches durch ESR-Messung charakterisiert werden konnte. Eine l{\"o}sungmittelabh{\"a}ngige Reaktion findet mit Trifluorophosphan statt, mit welchem die entsprechende instabile Borylenverbindung NMR-spektroskopisch untersucht werden konnte. Die Borazidspezien 169 und 170 sowie das Aminoboran 171 konnten durch Umsetzung von 89 mit Mesityl- und Phenylazid generiert und vollst{\"a}ndig charakterisiert werden. In Anlehnung an die Synthese von Fischercarbenkomplexen wurde 89 mit Organometallverbindungen umgesetzt, um die Reaktivit{\"a}t des CO-Liganden zu erforschen. Nach Umsetzungen mit Phenyllithium, Methyllithium oder Benzylkalium erfolgte die Methylierung in situ mittels Methyltriflat oder dem Meerwein-Salz [Me3O][BF4]. Die entstandenen Fischercaben-analogen Verbindungen konnten strukturell und spektroskopisch charakterisiert werden.}, subject = {Borylene}, language = {de} } @phdthesis{Englert2022, author = {Englert, Lukas}, title = {Synthese und Reaktivit{\"a}t Phosphan-stabilisierter Diborene}, doi = {10.25972/OPUS-24136}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241365}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die vorliegende Arbeit besch{\"a}ftigt sich mit der Synthese und Reaktivit{\"a}t von Phosphan-stabilisierten Diborenen. Der erste Teil beschreibt die Darstellung von Tetrabromdiboran(4)-Addukten mit zweiz{\"a}hnigen (84a-87c) und einz{\"a}hnigen Phosphanen (43a-c; 88a-89b), welche ausgehend von B2Br4(SMe2)2 (83) in einer Substitutionsreaktion in sehr guten Ausbeuten erhalten wurden. In fast allen F{\"a}llen gelang es mithilfe der Molek{\"u}lstrukturen im Festk{\"o}rper die Verbindungen n{\"a}her zu untersuchen. Dabei konnten erstmalig Phosphan-verbr{\"u}ckte Diboran(6)-Verbindungen 86a-87a strukturell charakterisiert werden. Eine Besonderheit stellt in diesem Zusammenhang der PBBP-Torsionswinkel α dar, der die Abwinklung zwischen den Phosphanliganden angibt und welcher mit steigender Sterik zunimmt, was auf attraktive Dispersionswechselwirkungen zwischen den organischen Resten zur{\"u}ckzuf{\"u}hren ist. Einige Addukte wurden experimentell auf ihr Redoxverhalten hin untersucht. Obwohl bei vielen Reduktionsversuchen Diboren-typische NMR-Signale beobachtet wurden, sind die meisten Produkte so instabil, dass keine weiteren Beweise f{\"u}r die erfolgreiche Darstellung der jeweiligen Diborene erbracht werden konnten. Nur f{\"u}r 88c gelang die zielgerichtete Reduktion zum Diboren 93c zu reduzieren. Die analysenreine Isolierung von 93c gelang jedoch nicht, sodass es in situ zum Diboren-{\"U}bergangsmetall-side-on Komplex 94 umgesetzt wurde. Quantenchemische Untersuchungen der Grenzorbitale zeigten, dass sehr wahrscheinlich die energetische Lage der MOs mit Anteilen auf den σ*-Orbitalen der B‒Br-Bindungen ausschlaggebend f{\"u}r eine erfolgreiche Reduktion von Bisphosphanaddukten zum Diboren ist. Allerdings stellt auch der r{\"a}umliche Anspruch der Phosphane einen entscheidenden Stabilit{\"a}tsfaktor f{\"u}r das entstehende Phosphan-stabilisierte Diboren dar. Weiterhin wurde das Portfolio an Phosphan-stabilisierten 1,2-Diaryldiborenen mit den Ver-bindungen 97a-98b erweitert und die Synthese derartiger Diborene in einer Eintopfsynthese optimiert. Außerdem gelang die erstmalige Darstellung Phosphan-stabilisierter Diborene mit Durylsubstituenten (98a/b), die sich aber, mitsamt ihren Brom-verbr{\"u}ckten Monoadduktvorstufen 96a/b, als unerwartet labil erwiesen. Die Diborene zeigen f{\"u}r diese Verbindungsklasse typische NMR-spektroskopische und r{\"o}ntgenkristallographische Messdaten. Zus{\"a}tzlich wurden 97a/b mittels UV/Vis-Spektroskopie und quantenchemischen Methoden n{\"a}her analysiert. Das Hauptaugenmerk der durchgef{\"u}hrten Forschungsarbeiten lag auf der Untersuchung der Reaktivit{\"a}t des Diborens 48a. Dessen B=B-Bindungsordnung konnte in zwei Reaktionen mit unterschiedlichen Oxidationsmitteln unter Bildung des Radikalkations [100]∙+ herabgesetzt werden. Eine Oxidation der B=B-Bindung gelang auch mit der Umsetzung von 48a mit Chalkogenen und chalkogenhaltigen Reagenzien. Unter anderem gelang mit der Darstellung des 1,2-Dimesityl-1,2-di(phenylseleno)diborans(4) (104) die Synthese eines seltenen Beispiels f{\"u}r ein strukturell aufgekl{\"a}rtes, selenhaltiges Diboran(4). Dabei konnte außerdem erstmals die vollst{\"a}ndige Freisetzung beider Lewis-Basen aus einem Diboren unter gleichzeitiger Reduktion der Bindungsordnung beobachtet werden. Weiterhin wurde 48a mit stickstoffhaltigen Heteroaromaten umgesetzt. Dabei lassen die spektroskopischen und quantenchemischen Daten ein Pyridin-stabilisiertes Diboren 105 vermuten. In weiteren Versuchen wurde 48a mit 2,2'-Bipyridin untersucht und ein Monoboran und das 1,4-Diaza-2,3- diborinin 106 erhalten. 106 wurde im Festk{\"o}rper und quantenchemisch n{\"a}her untersucht. Eine NICS-Analyse bescheinigt dem zentralen B2N2C2-Ring des Diborans(4) ein außer-ordentliches Maß an Aromatizit{\"a}t. Ferner war 48a in der Lage, Element-Wasserstoffbindungen zu aktivieren (E = B, Si, N, S). W{\"a}hrend f{\"u}r die Umsetzungen mit diversen Silanen nur {\"u}ber die Reaktionszusammensetzung spekuliert werden konnte, gelang die Strukturaufkl{\"a}rung zweier Produkte der Reaktion mit HBCat (110 und 111) mittels Einkristallr{\"o}ntgenstrukturanalyse. In diesem Zusammenhang gelang die Darstellung der sp2-sp3-Diborane(5) 112-113b in Umsetzungen von 48a mit einem Thiol bzw. mit Anilinderivaten in guten Ausbeuten. Die NMR-spektroskopischen und kristallographischen Daten der Produkte sind miteinander vergleichbar und liegen im erwarteten Bereich derartiger Verbindungen. Zus{\"a}tzlich konnte in den stickstoffhaltigen Produkten 113a/b die trans-Konfiguration der B=N-Doppelbindung mittels 1H-1H-NOESY-NMR-Experimenten best{\"a}tigt werden. Das Diboren 48a zeigt auch ein reichhaltiges Reaktivit{\"a}tsverhalten gegen{\"u}ber kleinen Molek{\"u}len. Nach dem Austausch der Schutzgasatmosph{\"a}re gegen N2O oder CO2 konnte die oxidative Zersetzung von 48a zum literaturbekannten Boroxinderivat 114 festgestellt werden. G{\"a}nzlich anders verlief die Reaktion von 48a mit CO, wobei ein interessanter, achtgliedriger Heterocyclus 115 gebildet wurde, der formal aus zwei gespaltenen CO-Molek{\"u}len und zwei Diborenen besteht. Die genaue Beschreibung der Bindungssituation innerhalb der BC(P)B-Einheit kann, anhand der Festk{\"o}rperstruktur von 115 und DFT-Berechnungen, mit literaturbekannten α-borylierten Phosphoryliden verglichen werden. Mit hoher Wahrscheinlichkeit liegt eine Mischform der mesomeren Grenzstrukturen 115-A, 115-B und 115-C vor, da f{\"u}r alle drei Strukturvorschl{\"a}ge experimentelle Hinweise gefunden werden k{\"o}nnen. Das Diboren 48a reagierte mit H2 ohne Katalysator, unter thermischer Belastung, erh{\"o}htem Druck und langer Reaktionszeit zu unterschiedlichen Produkten. Erste Umsetzungen f{\"u}hrten hierbei zum Produkt 118a, das in folgenden Hydrierungen aber nicht mehr reproduziert werden konnte. Stattdessen wurde die selektive Bildung der Monoborane 119a/b beobachtet. F{\"u}r beide Reaktivit{\"a}ten wurde je ein Reaktionsmechanismus quantenchemisch untersucht. Das Schl{\"u}sselintermediat ist dabei jeweils ein hochreaktives Intermediat Int3, welches vermutlich f{\"u}r eine Vielzahl an Reaktivit{\"a}ten von 48a verantwortlich ist. Das letzte Kapitel widmete sich unterschiedlichen Cycloadditionen von 48a mit verschiedenen unges{\"a}ttigten Substraten. Die Reaktivit{\"a}t gegen{\"u}ber Aziden konnte hierbei nicht vollst{\"a}ndig aufgekl{\"a}rt werden. Allerdings gelang es ein PMe3-stabilisiertes Phosphazen 122 als Nebenprodukt nachzuweisen und gezielt in einer Staudinger-Reaktion darzustellen. Mit Carbodiimiden reagierte das Diboren 48a unter photolytischen Bedingungen zu den 1,2,3-Azadiboretidinen 123a-c, wobei die Reaktionsgeschwindigkeit stark vom sterischen Anspruch des Carbodiimids abh{\"a}ngig war. Das Azadiboretidin 123a konnte im Festk{\"o}rper n{\"a}her untersucht werden und stellt ein seltenes Beispiel f{\"u}r einen solchen Heterocyclus dar. Die thermische Umsetzung von 48a mit den Carbodiimiden lieferte hingegen ein noch nicht vollst{\"a}ndig aufgekl{\"a}rtes Produkt. Anhand der spektroskopischen Daten wird die Darstellung eines NHCs mit Diboran(4)-R{\"u}ckgrat der Art B2Mes2(NiPr)2C: (124a) vermutet. Quantenchemische Untersuchungen sagen f{\"u}r 124a {\"a}hnliche Bindungsparameter wie f{\"u}r ein literaturbekanntes π-acides NHC voraus. Die Reaktion von 48a mit terminalen Alkinen f{\"u}hrte zielgerichtet zu PMe3-stabilisierten 1,3-Dihydro-1,3-diboreten 126a-d. In L{\"o}sung konnten f{\"u}r 126c/d zus{\"a}tzlich die jeweiligen Konstitutionsisomere 127c/d mit Anteilen von unter 10\% NMR-spektroskopisch beobachtet werden. Im Festk{\"o}rper wird hingegen nicht das Diboret 126d, sondern ausschließlich das Konstitutionsisomer 127d beobachtet. Die Lewis-Formel der Diborete legt nahe, dass ein elektronenarmes, dreifach koordiniertes Kohlenstoffatom in der BCB-Einheit vorliegt, was im 13C{1H}-NMR-Spektrum mit den entsprechenden Signalen best{\"a}tigt wird. Eine elektronische Delokalisation wird mit den ermittelten B‒C-Atomabst{\"a}nden innerhalb der BCsp2B-Einheiten von 126a-c und 127d unterst{\"u}tzt. Die P‒Csp2-Bindung in 127d weist zudem einen kurzen P=C-Bindungsabstand auf, was einen sehr hohen π-Anteil vermuten l{\"a}sst. Die einmalige Beschreibung des C‒H-Aktivierungsprodukts 131 im Festk{\"o}rper gibt einen Hinweis auf eine anf{\"a}ngliche [2+2]-Cycloaddition zwischen der B=B-Doppelbindung und dem terminalen Alkin, die {\"u}ber eine 1,3-Umlagerung zur Bildung der 1,3-Diborete f{\"u}hrt. Ferner gelang unter den identischen Reaktionsbedingungen aus 48a und 1,4-Diethinylbenzol die Darstellung der Mono- und Bis(1,3-dihydro-1,3-diborete) 128 und 129, wobei 129 nur im Festk{\"o}rper genauer untersucht werden konnte. Die Umsetzung von 48a mit 1,3,5-Triethinylbenzol ergab ein Produktgemisch der Form (B2Mes2(PMe3)HCC)n(C6H3)(CCH)3-n (130-n; n = 1, 2, 3), welches Hinweise auf die zweifache bzw. dreifache Diboretbildung lieferte. DFT-Berechnungen sagen f{\"u}r das Bisdiboret 129 eine Kommunikation zwischen beiden Heterocyclen {\"u}ber den zentralen Benzolring voraus, was die Ursache f{\"u}r die beobachtete Fluoreszenz sein k{\"o}nnte. Das Diboren 48a reagierte zudem mit Diazabutadienen unter thermischen Bedingungen in inversen Diels-Alder-Reaktionen zu 1,2,3,4-Tetraaryl-1,4-diaza-2,3-diborininen 132a-e. Dies stellt einen neuen Zugang zu dieser Substanzklasse dar. Dabei zeigte sich eine direkte Korrelation zwischen der Reaktionszeit und dem r{\"a}umlichen Anspruch der Diazabutadiene. Die erfolgreiche Aufarbeitung der 1,4-Diaza-2,3-diborinine ist aufgrund ihrer hohen L{\"o}slichkeit in g{\"a}ngigen L{\"o}sungsmitteln wesentlich vom Kristallisationsverhalten der Produkte abh{\"a}ngig. Die analoge Umsetzung unter photochemischen Bedingungen gab Hinweise darauf, dass diese Reaktion dem Mechanismus einer inversen [4+2]-Cycloaddition folgt. Bemerkenswert ist die hohe Stabilit{\"a}t der Diborane(4) 132b/c gegen{\"u}ber Luft und Wasser, die vermutlich auf der kinetischen Stabilisierung durch die ortho- Methylgruppen der Stickstoff-gebundenen Aromaten beruht. Im Gegensatz dazu wurde bei der Reaktion zwischen 48a und dem Diazabutadien (MesN)2C2Mes2 das 1,2,3,4-Tetramesityl-5,6-dimethyl-1,4-diaza-2,3-diborinin 132e nur in Spuren nachgewiesen. Unter den gew{\"a}hlten Bedingungen wurde stattdessen Verbindung 133 gebildet. Die systematische, experimentelle Untersuchung dieser Reaktivit{\"a}t wurde jedoch im Rahmen dieser Arbeit nicht durchgef{\"u}hrt. Die Schl{\"u}sselschritte des Reaktionsmechanismus zur Bildung von 133 f{\"u}hren h{\"o}chstwahrscheinlich wieder {\"u}ber das Intermediat Int3. Nach einer 1,2-Wanderung eines Mesitylsubstituenten wird das Monophosphan-stabilisierte Zwitterion Int13a gebildet, welches in seiner Grenzstruktur Int13b als Borylen beschrieben werden kann. Eine anschließende intramolekulare C‒H-Aktivierung resultiert im Diboran(5) 133. Mit dieser Arbeit ist es gelungen, neue Erkenntnisse {\"u}ber die Chemie Phosphan-stabilisierter Diborene zu erhalten. Die labil gebundenen Phosphane er{\"o}ffnen diesen Diborenen eine einzigartige Reaktivit{\"a}t, die bei den NHC-Vertretern nicht gefunden wird. In der Zukunft k{\"o}nnten neue Konzepte entwickelt werden dieses Reaktionsverhalten weiter zu nutzen. W{\"u}nschenswert w{\"a}re es die Diboren-Monomere miteinander zu Ketten zu verkn{\"u}pfen.}, subject = {Bor}, language = {de} } @phdthesis{Toksabay2022, author = {Toksabay, Sinem}, title = {Synthesis and on surface self assembly properties of pi extended tribenzotriquinacenes}, doi = {10.25972/OPUS-24573}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245734}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Tribenzotriquinacene (TBTQ) is a polycyclic aromatic framework with a particularly rigid, C3v symmetrical, bowl-shaped core bearing three mutually fused indane wings. It has been discussed as a defect center for a nanographene by Kuck and colleagues. Therefore, extended TBTQ structures are promising models for saturated defect structures in graphene and graphene like molecules and could be used to investigate the role of defects for the electronic properties of graphene. With this motivation, three different pi-extended TBTQ derivatives have been synthesized in this work. Several different Scholl reaction conditions were tried to obtain fully annulated product of hexaphenyl substituted TBTQ. The desired benzannulated TBTQ derivative could not be obtained due to unfavourable electron density in the respective positions of the molecule and increased reactivity of the bay position of the precursor. As an another method for benzannulation is the on-surface synthesis of graphene flakes and can be carried out using electron beams e.g. in a tunneling microscope (STM). According to our previous research, the parent system TBTQ and centro-methyl TBTQ on silver and gold surfaces showed that the gas phase deposition of these molecules gives rise to the formation of highly ordered two-dimensional assemblies with unique structural features. This shows the feasibility for the formation of defective graphene networks starting from the parent structures. Therefore, the same deposition technique was used to deposit Me-TBTQ(OAc)3Ph6, and investigate the molecular self-assembly properties directly on the surface of Cu (111). In summary, the substrate temperature dependent self-assembly of Me-TBTQ(OAc)3Ph6 molecules on Cu(111), shows the following evolution of orientations. At room temperature, molecules form dimers, which construct a higher-coverage honeycomb lattice. Furthermore, one of the acetyl group located in the bay positions of the TBTQ core is cleaved and the remaining two induce the metal-molecule interaction. It was presumed that by increasing the temperature to 393 K, the remaining acetyl and methyl groups would beeliminated from the molecular structure.In addition, the smaller TBTQ-Ph6 molecules preferably lie flat on Cu(111) crystal and allowing the molecules to settle into a C3-symmetry and form a dense hexagonal structure.}, subject = {Triquinacenderivate}, language = {en} } @phdthesis{Fey2022, author = {Fey, Christina}, title = {Establishment of an intestinal tissue model for pre-clinical screenings}, doi = {10.25972/OPUS-24410}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244107}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The small intestine represents a strong barrier separating the lumen from blood circulation thereby playing a major role in the absorption and the transport of pharmacological agents prior to their arrival on the respective target site. In order to gain more knowledge about specialized uptake mechanisms and risk assessment for the patient after oral admission of drugs, intestinal in vitro models demonstrating a close similarity to the in vivo situation are needed. In the past, cell line-based in vitro models composed of Caco-2 cells cultured on synthetic cell carriers represented the "gold standard" in the field of intestinal tissue engineering. Expressive advantages of these models are a reproducible, cost-efficient and standardized model set up, but cell function can be negatively influenced by the low porosity or unwanted molecular adhesion effects of the artificial scaffold material. Natural extracellular matrices (ECM) such as the porcine decellularized small intestinal submucosa (SIS) are used as alternative to overcome some common drawbacks; however, the fabrication of these scaffolds is time- and cost-intensive, less well standardized and the 3Rs (replacement, reduction, refinement) principle is not entirely fulfilled. Nowadays, biopolymer-based scaffolds such as the bacterial nanocellulose (BNC) suggest an interesting option of novel intestinal tissue engineered models, as the BNC shows comparable features to the native ECM regarding fiber arrangement and hydrophilic properties. Furthermore, the BNC is of non-animal origin and the manufacturing process is faster as well as well standardized at low costs. In this context, the first part of this thesis analyzed the BNC as alternative scaffold to derive standardized and functional organ models in vitro. Therefore, Caco-2 cells were cultured on two versions of BNC with respect to their surface topography, the unmodified BNC as rather smooth surface and the surface-structured BNC presenting an aligned fiber arrangement. As controls, Caco-2 in vitro models were set up on PET and SIS matrices. In this study, the BNC-based models demonstrated organ-specific properties comprising typical cellular morphologies, a characteristic tight junction protein expression profile, representative ultrastructural features and the formation of a tight epithelial barrier together with a corresponding transport activity. In summary, these results validated the high quality of the BNC-based Caco-2 models under cost-efficient conditions and their suitability for pre-clinical research purposes. However, the full functional diversity of the human intestine cannot be presented by Caco-2 cells due to their tumorigenic background and their exclusive representation of mature enterocytes. Next to the scaffold used for the setup of in vitro models, the cellular unit mainly drives functional performance, which demonstrates the crucial importance of mimicking the cellular diversity of the small intestine in vitro. In this context, intestinal primary organoids are of high interest, as they show a close similarity to the native epithelium regarding their cellular diversity comprising enterocytes, goblet cells, enteroendocrine cells, paneth cells, transit amplifying cells and stem cells. In general, such primary organoids grow in a 3D Matrigel® based environment and a medium formulation supplemented with a variety of growth factors to maintain stemness, to inhibit differentiation and to stimulate cell migration supporting long term in vitro culture. Intestinal primary spheroid/organoid cultures were set up as Transwell®-like models on both BNC variants, which resulted in a fragmentary cell layer and thereby unfavorable properties of these scaffold materials under the applied circumstances. As the BNC manufacturing process is highly flexible, surface properties could be adapted in future studies to enable a good cell adherence and barrier formation for primary intestinal cells, too. However, the application of these organoid cultures in pre-clinical research represents an enormous challenge, as the in vitro culture is complex and additionally time- and cost-intensive. With regard to the high potential of primary intestinal spheroids/organoids and the necessity of a simplified but predictive model in pre-clinical research purposes, the second part of this thesis addressed the establishment of a primary-derived immortalized intestinal cell line, which enables a standardized and cost-efficient culture (including in 2D), while maintaining the cellular diversity of the organoid in vitro cultures. In this study, immortalization of murine and human intestinal primary organoids was induced by ectopic expression of a 10- (murine) or 12 component (human) pool of genes regulating stemness and the cell cycle, which was performed in cooperation with the InSCREENeX GmbH in a 2D- and 3D-based transduction strategy. In first line, the established cell lines (cell clones) were investigated for their cell culture prerequisites to grow under simplified and cost-efficient conditions. While murine cell clones grew on uncoated plastic in a medium formulation supplemented with EGF, Noggin, Y-27632 and 10\% FCS, the human cell clones demonstrated the necessity of a Col I pre coating together with the need for a medium composition commonly used for primary human spheroid/organoid cultures. Furthermore, the preceding analyses resulted in only one human cell clone and three murine cell clones for ongoing characterization. Studies regarding the proliferative properties and the specific gene as well as protein expression profile of the remaining cell clones have shown, that it is likely that transient amplifying cells (TACs) were immortalized instead of the differentiated cell types localized in primary organoids, as 2D, 3D or Transwell®-based cultures resulted in slightly different gene expression profiles and in a dramatically reduced mRNA transcript level for the analyzed marker genes representative for the differentiated cell types of the native epithelium. Further, 3D cultures demonstrated the formation of spheroid-like structures; however without forming organoid-like structures due to prolonged culture, indicating that these cell populations have lost their ability to differentiate into specific intestinal cell types. The Transwell®-based models set up of each clone exhibit organ-specific properties comprising an epithelial-like morphology, a characteristic protein expression profile with an apical mucus-layer covering the villin-1 positive cell layer, thereby representing goblet cells and enterocytes, together with representative tight junction complexes indicating an integer epithelial barrier. The proof of a functional as well as tight epithelial barrier in TEER measurements and in vivo-like transport activities qualified the established cell clones as alternative cell sources for tissue engineered models representing the small intestine to some extent. Additionally, the easy handling and cell expansion under more cost-efficient conditions compared to primary organoid cultures favors the use of these newly generated cell clones in bioavailability studies. Altogether, this work demonstrated new components, structural and cellular, for the establishment of alternative in vitro models of the small intestinal epithelium, which could be used in pre-clinical screenings for reproducible drug delivery studies.}, subject = {D{\"u}nndarm}, language = {en} } @phdthesis{Mueller2022, author = {M{\"u}ller, Stefan}, title = {Coherent Multiple-Quantum Multidimensional Fluorescence Spectroscopy}, doi = {10.25972/OPUS-24411}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244113}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {This thesis describes novel concepts for the measurement of the static and dynamic properties of the electronic structure of molecules and nanocrystals in the liquid phase by means of coherent fluorescence-detected spectroscopy in two and three frequency dimensions. These concepts are based on the systematic variation ("phase cycling") of a sequence of multiple time-delayed femtosecond excitation pulses in order to decode a multitude of novel nonlinear signals from the resulting phase-dependent fluorescence signal. These signals represent any permutation of correlations between zero-, one-, two-, and three-quantum coherences. To this end, two new phase-cycling schemes have been developed which can simultaneously resolve and discriminate several nonlinear signals of sixth order, including those of the fourth order of nonlinearity. By means of the sixth-order signals recorded in this work, static properties of highly excited electronic states in molecules such as their energies, transition dipole moments, and relative displacement of electronic potential surfaces, as well as dynamic properties in terms of their relaxation kinetics, can be ascertained. Furthermore, it was shown that these signals are suitable for the characterization of exciton-exciton correlations in colloidal quantum dots and for the measurement of ultrafast exciton-exciton annihilation in molecular aggregates. The experiments performed in this thesis mark an important step towards the complete characterization of the nonlinear response of quantum systems. In view of this, the concept of fluorescence-detected multiple-quantum coherence multidimensional spectroscopy introduced here offers a unified, systematic approach. In virtue of the technical advantages such as the use of a single excitation beam and the absence of nonresonant contributions, the measurement protocols developed here can be directly transferred to other incoherent observables and to sample systems in other states of matter. Furthermore, the approaches presented here can be systematically extended to higher frequency dimensions and higher orders of nonlinearity.}, subject = {Coherent Multidimensional Spectroscopy}, language = {en} } @phdthesis{Hagspiel2022, author = {Hagspiel, Stephan Alexander}, title = {Synthesis and Reactivity of Pseudohalide-substituted Boranes and Borylenes}, doi = {10.25972/OPUS-24945}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249459}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {This work involves the synthesis and reactivity of pseudohalide-substituted boranes and borylenes. A series of compounds of the type (CAAC)BR2Y (CAAC = cyclic alkyl(amino)carbene; R = H, Br; Y = CN, NCS, PCO) were prepared first. The two-electron reduction of (CAAC)BBr2Y (Y = CN, NCS) in the presence of a second Lewis base L (L = N-heterocyclic carbene) resulted in the formation of the corresponding doubly Lewis base-stabilized pseudohaloborylenes (CAAC)(L)BY. These borylenes show versatile reactivity patterns, including their oxidation to the corresponding radical cations, coordination via the respective pseudohalide substituent to group 6 metal carbonyl complexes, as well as a boron-centered protonation with Br{\o}nsted acids to boronium cations. Reduction of (CAAC)BBr2(NCS) in the absence of a second donor ligand, led to the formation of boron-doped thiazolothiazoles via reductive dimerization of two isothiocyanatoborylenes. These B,N,S-heterocycles possess a low degree of aromaticity as well as interesting photophysical properties and can furthermore be protonated as well as hydroborated. Additionally, CAAC adducts of the parent boraphosphaketene (CAAC)BH2(PCO) could be prepared, which readily reacted with boroles [Ph4BR'] (R' = aryl) via decarbonylation in a ring expansion reaction. The obtained 1,2-phosphaborinines represent B,P-isosteres of benzene and consequently could be coordinated to metal carbonyl complexes of the chromium triade via η6-coordination, resulting in new half-sandwich complexes thereof.}, subject = {Borylene}, language = {en} } @phdthesis{Dombrovski2022, author = {Dombrovski, Veaceslav}, title = {Software Framework to Support Operations of Nanosatellite Formations}, isbn = {978-3-945459-38-6}, doi = {10.25972/OPUS-24931}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249314}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Since the first CubeSat launch in 2003, the hardware and software complexity of the nanosatellites was continuosly increasing. To keep up with the continuously increasing mission complexity and to retain the primary advantages of a CubeSat mission, a new approach for the overall space and ground software architecture and protocol configuration is elaborated in this work. The aim of this thesis is to propose a uniform software and protocol architecture as a basis for software development, test, simulation and operation of multiple pico-/nanosatellites based on ultra-low power components. In contrast to single-CubeSat missions, current and upcoming nanosatellite formation missions require faster and more straightforward development, pre-flight testing and calibration procedures as well as simultaneous operation of multiple satellites. A dynamic and decentral Compass mission network was established in multiple active CubeSat missions, consisting of uniformly accessible nodes. Compass middleware was elaborated to unify the communication and functional interfaces between all involved mission-related software and hardware components. All systems can access each other via dynamic routes to perform service-based M2M communication. With the proposed model-based communication approach, all states, abilities and functionalities of a system are accessed in a uniform way. The Tiny scripting language was designed to allow dynamic code execution on ultra-low power components as a basis for constraint-based in-orbit scheduler and experiment execution. The implemented Compass Operations front-end enables far-reaching monitoring and control capabilities of all ground and space systems. Its integrated constraint-based operations task scheduler allows the recording of complex satellite operations, which are conducted automatically during the overpasses. The outcome of this thesis became an enabling technology for UWE-3, UWE-4 and NetSat CubeSat missions.}, subject = {Kleinsatellit}, language = {en} } @phdthesis{Kryven2022, author = {Kryven, Myroslav}, title = {Optimizing Crossings in Circular-Arc Drawings and Circular Layouts}, isbn = {978-3-95826-174-7}, doi = {10.25972/WUP-978-3-95826-175-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245960}, school = {Universit{\"a}t W{\"u}rzburg}, pages = {viii, 129}, year = {2022}, abstract = {A graph is an abstract network that represents a set of objects, called vertices, and relations between these objects, called edges. Graphs can model various networks. For example, a social network where the vertices correspond to users of the network and the edges represent relations between the users. To better see the structure of a graph it is helpful to visualize it. The research field of visualizing graphs is called Graph Drawing. A standard visualization is a node-link diagram in the Euclidean plane. In such a representation the vertices are drawn as points in the plane and edges are drawn as Jordan curves between every two vertices connected by an edge. Edge crossings decrease the readability of a drawing, therefore, Crossing Optimization is a fundamental problem in Graph Drawing. Graphs that can be drawn with few crossings are called beyond-planar graphs. The topic that deals with definition and analysis of beyond-planar graphs is called Beyond Planarity and it is an important and relatively new research area in Graph Drawing. In general, beyond planar graphs posses drawings where edge crossings are restricted in some way. For example, the number of crossings may be bounded by a constant independent of the size of the graph. Crossings can also be restricted locally by, for example, restricting the number of crossings per edge, restricting the number of pairwise crossing edges, or bounding the crossing angle of two edges in the drawing from below. This PhD thesis defines and analyses beyond-planar graph classes that arise from such local restrictions on edge crossings.}, subject = {Graphenzeichnen}, language = {en} } @phdthesis{Rempel2022, author = {Rempel, Anna}, title = {Synthese und Reaktivit{\"a}t von Boryldiazenidokomplexen}, doi = {10.25972/OPUS-24741}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-247415}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die vorliegende Arbeit befasst sich mit der Synthese, Charakterisierung und Reaktivit{\"a}t von Boryldiazenidokomplexen. Im ersten Abschnitt wird die Synthese von neuartigen Boryldiazenidokomplexen behandelt. Im zweiten Teil werden Studien zu den Reaktivit{\"a}ten dieser Verbindungen gegen{\"u}ber Elektrophilen, Lewis-Basen sowie Reaktionen an den Element-Halogen-Bindungen vorgestellt.}, subject = {{\"U}bergangsmetallkomplexe}, language = {de} } @phdthesis{Ryma2022, author = {Ryma, Matthias}, title = {Exploiting the Thermoresponsive Properties of Poly(2-oxazoline)s for Biofabrication}, doi = {10.25972/OPUS-24746}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-247462}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {In this thesis, non-modified POx, namely PnPrOx and PcycloPrOx, with an LCST in the physiological range between 20 and 37°C have been utilized as materials for three different biofabrication approaches. Their thermoresponsive behavior and processability were exploited to establish an easy-to-apply coating for cell sheet engineering, a novel method to create biomimetic scaffolds based on aligned fibrils via Melt Electrowriting (MEW) and the application of melt electrowritten sacrificial scaffolds for microchannel creation for hydrogels. Chapter 3 describes the establishment of a thermoresponsive coating for tissue culture plates. Here, PnPrOx was simply dissolved in water and dried in well plates and petri dishes in an oven. PnPrOx adsorbed to the surface, and the addition of warm media generated a cell culture compatible coating. It was shown that different cell types were able to attach and proliferate. After confluency, temperature reduction led to the detachment of cell sheets. Compared to standard procedures for surface coating, the thermoresponsive polymer is not bound covalently to the surface and therefore does not require specialized equipment and chemical knowledge. However, it should be noted that the detachment of the cell layer requires the dissolution of the PnPrOx-coating, leading to possible polymer contamination. Although it is only a small amount of polymer dissolved in the media, the detached cell sheets need to be washed by media exchange for further processing if required. ...}, subject = {Thermoresponsive Polymere}, language = {en} } @phdthesis{Lehenberger2022, author = {Lehenberger, Maximilian}, title = {Ecology and Evolution of symbiotic microbial communities in fungus farming ambrosia beetles}, publisher = {Fungal Ecology, Frontiers in Microbiology, Deutsche Gesellschaft f{\"u}r allgemeine und angewandte Entomologie}, doi = {10.25972/OPUS-24154}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241546}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Within my PhD project I gained several novel insights into the poorly investigated symbiotic world of fungus farming ambrosia beetles and their bark beetle ancestors, where I especially focused on physiological interactions and capabilities of associated fungal symbionts. Here, (i) I could confirm the association of mutualistic Phialophoropsis fungi with the ambrosia beetle genus Trypodendron and found hints for a possible new Phialophoropsis species in T. signatum and T. domesticum. Moreover, I could show that mutualistic fungi of Trypodendron ambrosia beetles are able to decompose major woody polysaccharides such as cellulose and xylan. Additionally, (ii) I provided the first images using micro-computed tomography (µCT) of the formerly unknown structure of the mycetangium of Trypodendron leave. (iii) I could confirm a general tolerance towards ethanol in mutualistic ambrosia beetle fungi, while antagonistic fungi as well as most examined fungal bark beetle associates (e.g. possibly tree-defense detoxifying species) were highly sensitive to even low concentrations of ethanol. Further, (iv) I found that natural galleries of ambrosia beetles are highly enriched with several biologically important elements (such as N, P, S, K, Mg) compared to the surrounding woody tissue and suggest that mutualistic fungi are translocating and concentrating elements from the immediate surrounding xylem to the beetles galleries. Furthermore, (v) I could show that various fungi associated with bark and ambrosia beetles (mutualists, possibly beneficial symbionts) are emitting several volatile organic compounds mostly within aliphatic and aromatic alcohols and esters, while non-mutualistic and free living species were generally emitting a lower number and amount of volatiles. Finally, especially bark and ambrosia beetle fungi were found to incorporate several amino acids, from which some are especially important for the production of certain volatile organic compounds. Amino acid content also indicated a higher nutritional value for certain species. Here, I propose that especially volatile organic compounds are widespread key players in maintaining various symbioses between fungi and beetles, as already proven by a recent study on the bark beetle Ips typographus (as well as for some other bark beetle-fungus symbioses, see summary in Kandasamy et al. 2016) and also suggested for ambrosia beetles.}, language = {en} } @phdthesis{Giampaolo2022, author = {Giampaolo, Sabrina}, title = {Role of the transcription factor NFATc1 during the early stages of thymocyte development}, doi = {10.25972/OPUS-24639}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246394}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {T lymphocytes (T cells) represent one of the major cell populations of the immune system. Named by the place of their development, the thymus, several types can be distinguished as the αβ T cells, the γδ T cells, the mucosa-associated invariant T cells (MAIT), and the natural killer T (NKT) cells. The αβ lineages of CD4+ THelper and the CD8+ T cytotoxic cells with the T cell receptor (TCR) composed of α- and β-chain are major players of the adaptive immune system. In the thymus, CD4+ and CD8+ single positive (SP) αβ cells represent the ultimate result of positive and negative selection of CD4+CD8+ double positive (DP) thymocytes. The DP population derives from the double negative (DN) thymocytes that develop from bone marrow-derived progenitors through different stages (DN1-DN4) that are characterized by CD25 and CD44 surface expression. NFATc1, a member of the Nuclear Factor of Activated T cells (NFAT) transcription factors family, is critically involved in the differentiation and function of T cells. During thymocyte development, the nuclear expression of NFATc1 reaches the highest level at the DN3 (CD44-CD25+) stage. The hematopoietic cell-specific ablation of NFATc1 activity results in an arrest of thymocyte differentiation at the DN1 (CD44+CD25-) stage. On the other hand, over-expression of a constitutively active version of NFATc1 results in an impaired transition of DN3 cells to the DN4 (CD44-CD25-) stage, suggesting that a certain threshold level of NFATc1 activity is critical at this point. ChIP-seq and RNA-seq analysis allowed us the identification of NFATc1/A target genes involved in lineage development as the Tcra and Tcrb gene loci. Furthermore, we identified multiple NFATc1-regulated genes that are involved in γδ T cell development. In the mouse models, Rag1Cre-Nfatc1fl/fl and Rag1Cre-E2fl/fl, in which the activity of NFATc1 or inducible NFATc1 in the latter is impaired during the early stages of thymocyte development, we observed increased numbers of γδ T cells. These γδ T cells showed an unusual overexpression of CD4, a lack of CD24 expression, and overexpression of the anti-apoptotic gene Bcl2a1a. We hypothesize that during the DN stages NFATc1 plays an important role in regulating crucial steps of αβ thymocyte development and when NFATc1 activity is missing this may disturb αβ development resulting in alternative cell fates like γδ T cells.}, subject = {Thymocytes}, language = {en} } @phdthesis{Kortmann2022, author = {Kortmann, Mareike}, title = {Biodiversity and recreation - Optimizing tourism and forest management in forests affected by bark beetles}, doi = {10.25972/OPUS-24031}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-240317}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Forests are multi-functional system, which have to fulfil different objectives at the same time. The main functions include the production of wood, storage of carbon, the promotion of biological diversity and the provision of recreational space. Yet, global forests are affected by large and intense natural disturbances, like bark beetle infestations. While natural disturbances threaten wood production and are perceived as 'catastrophe' diminishing recreational value, biodiversity can benefit from the disturbance-induced changes in forest structures. This trade-off poses a dilemma to managers of bark beetle affected stands, particularly in protected areas designated to both nature conservation and recreation. Forest landscapes need a sustainable management concept aligning these different objectives. In order to support this goal with scientific knowledge, the aim of this work is to analyse ecological and social effects along a gradient of different disturbance severities. In this context, I studied the effects of a disturbance severity gradient on the diversity of different taxonomic groups including vascular plants, mosses, lichens, fungi, arthropods and birds in five national parks in Central Europe. To analyse the recreational value of the landscape I conducted visitor surveys in the same study areas in which the biodiversity surveys were performed. To analyse possible psychological or demographic effects on preferences for certain disturbance intensities, an additional online survey was carried out.}, subject = {Borkenk{\"a}fer}, language = {en} } @phdthesis{Kuhlemann2022, author = {Kuhlemann, Alexander}, title = {Bioorthogonal labeling of neuronal proteins using super-resolution fluorescence microscopy}, doi = {10.25972/OPUS-24373}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-243731}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The synaptic cleft is of central importance for synaptic transmission, neuronal plasticity and memory and thus well studied in neurobiology. To target proteins of interest with high specificity and strong signal to noise conventional immunohistochemistry relies on the use of fluorescently labeled antibodies. However, investigations on synaptic receptors remain challenging due to the defined size of the synaptic cleft of ~20 nm between opposing pre- and postsynaptic membranes. At this limited space, antibodies bear unwanted side effects such as crosslinking, accessibility issues and a considerable linkage error between fluorophore and target of ~10 nm. With recent single molecule localization microscopy (SMLM) methods enabling localization precisions of a few nanometers, the demand for labeling approaches with minimal linkage error and reliable recognition of the target molecules rises. Within the scope of this work, different labeling techniques for super-resolution fluorescence microscopy were utilized allowing site-specific labeling of a single amino acid in synaptic proteins like kainate receptors (KARs), transmembrane α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor regulatory proteins (TARPs), γ-aminobutyric acid type A receptors (GABA-ARs) and neuroligin 2 (NL2). The method exploits the incorporation of unnatural amino acids (uAAs) in the protein of interest using genetic code expansion (GCE) via amber suppression technology and subsequent labeling with tetrazine functionalized fluorophores. Implementing this technique, hard-to-target proteins such as KARs, TARPs and GABA-ARs could be labeled successfully, which could only be imaged insufficiently with conventional labeling approaches. Furthermore, functional studies involving electrophysiological characterization, as well as FRAP and FRET experiments validated that incorporation of uAAs maintains the native character of the targeted proteins. Next, the method was transferred into primary hippocampal neurons and in combination with super-resolution microscopy it was possible to resolve the nanoscale organization of γ2 and γ8 TARPs. Cluster analysis of dSTORM localization data verified synaptic accumulation of γ2, while γ8 was homogenously distributed along the neuron. Additionally, GCE and bioorthogonal labeling allowed visualization of clickable GABA-A receptors located at postsynaptic compartments in dissociated hippocampal neurons. Moreover, saturation experiments and FRET imaging of clickable multimeric receptors revealed successful binding of multiple tetrazine functionalized fluorophores to uAA-modified dimeric GABA-AR α2 subunits in close proximity (~5 nm). Further utilization of tetrazine-dyes via super-resolution microscopy methods such as dSTORM and click-ExM will provide insights to subunit arrangement in receptors in the future. This work investigated the nanoscale organization of synaptic proteins with minimal linkage error enabling new insights into receptor assembly, trafficking and recycling, as well as protein-protein interactions at synapses. Ultimately, bioorthogonal labeling can help to understand pathologies such as the limbic encephalitis associated with GABA-AR autoantibodies and is already in application for cancer therapies.}, subject = {microscopy}, language = {en} } @phdthesis{Drescher2022, author = {Drescher, Regina}, title = {Neue Aluminiumheterocyclen: Darstellung und Eigenschaften von Aluminolen und Aluminafluorenen}, doi = {10.25972/OPUS-24652}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246523}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die Vorliegende Arbeit befasst sich mit der Darstellung und Reaktivit{\"a}t von Aluminolen, als auch Aluminafluorenen. Die Aluminole gehen eine Ringerweiterungsreaktion mit organischen Aziden ein, welche zur Bildung von sechsgliedrigen Aluminium-Stickstoff-Heterocyclen, den ersten nicht annulierten 1,2 Azaaluminabenzolen f{\"u}hrt. Weiterhin findet die Ringerweiterung des Aluminols mit einem Nitron, einem Iminoboran und einem Amin-N-Oxid statt, wodurch neue sechs-, sieben- und achtgliedrige cyclische Spezies mit hohem Heteroatomgehalt entstehen. Insgesamt wurden f{\"u}nf neue Aluminafluorene hergestellt, die je nach Substituent am Aluminiumzentrum unterschiedliche Strukturen aufweisen. Ihre relativer Lewis-S{\"a}ure-St{\"a}rke wurde mit der Gutmann-Beckett-Methode ermittelt. Neben der Bildung von Addukten mit NHCs, CAAC und DMAP, wurde in das Bromaluminiumfluoren auch (tert-Butylimino)mesitylboran insertiert, welches zur Bildung eines siebengliedrigen Aluminacyclus f{\"u}hrte.}, subject = {Aluminiumverbindungen}, language = {de} } @phdthesis{Boetzl2022, author = {B{\"o}tzl, Fabian Alexander}, title = {The influence of crop management and adjacent agri-environmental scheme type on natural pest control in differently structured landscapes}, doi = {10.25972/OPUS-24140}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241400}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Summary Chapters I \& II: General Introduction \& General Methods Agriculture is confronted with a rampant loss of biodiversity potentially eroding ecosystem service potentials and adding up to other stressors like climate change or the consequences of land-use change and intensive management. To counter this 'biodiversity crisis', agri-environment schemes (AES) have been introduced as part of ecological intensification efforts. These AES combine special management regimes with the establishment of tailored habitats to create refuges for biodiversity in agricultural landscapes and thus ensure biodiversity mediated ecosystem services such as pest control. However, little is known about how well different AES habitats fulfil this purpose and whether they benefit ecosystem services in adjacent crop fields. Here I investigated how effective different AES habitats are for restoring biodiversity in different agricultural landscapes (Chapter V) and whether they benefit natural pest control in adjacent oilseed rape (Chapter VI) and winter cereal fields (Chapter VII). I recorded biodiversity and pest control potentials using a variety of different methods (Chapters II, V, VI \& VII). Moreover, I validated the methodology I used to assess predator assemblages and predation rates (Chapters III \& IV). Chapter III: How to record ground dwelling predators? Testing methodology is critical as it ensures scientific standards and trustworthy results. Pitfall traps are widely used to record ground dwelling predators, but little is known about how different trap types affect catches. I compared different types of pitfall traps that had been used in previous studies in respect to resulting carabid beetle assemblages. While barrier traps collected more species and deliver more complete species inventories, conventional simple pitfall traps provide reliable results with comparatively little handling effort. Placing several simple pitfall traps in the field can compensate the difference while still saving handling effort.   Chapter IV: How to record predation rates? A plethora of methods has been proposed and used for recording predation rates, but these have rarely been validated before use. I assessed whether a novel approach to record predation, the use of sentinel prey cards with glued on aphids, delivers realistic results. I compared different sampling efforts and showed that obtained predation rates were similar and could be linked to predator (carabid beetle) densities and body-sizes (a proxy often used for food intake rates). Thus, the method delivers reliable and meaningful predation rates. Chapter V: Do AES habitats benefit multi-taxa biodiversity? The main goal of AES is the conservation of biodiversity in agricultural landscapes. I investigated how effectively AES habitats with different temporal continuity fulfil this goal in differently structured landscapes. The different AES habitats investigated had variable effects on local biodiversity. Temporal continuity of AES habitats was the most important predictor with older, more temporally continuous habitats harbouring higher overall biodiversity and different species assemblages in most taxonomic groups than younger AES habitats. Results however varied among taxonomic groups and natural enemies were equally supported by younger habitats. Semi-natural habitats in the surrounding landscape and AES habitat size were of minor importance for local biodiversity and had limited effects. This stresses that newly established AES habitats alone cannot restore farmland biodiversity. Both AES habitats as well as more continuous semi-natural habitats synergistically increase overall biodiversity in agricultural landscapes. Chapter VI: The effects of AES habitats on predators in adjacent oilseed rape fields Apart from biodiversity conservation, ensuring ecosystem service delivery in agricultural landscapes is a crucial goal of AES. I therefore investigated the effects of adjacent AES habitats on ground dwelling predator assemblages in oilseed rape fields. I found clear distance decay effects from the field edges into the field centres on both richness and densities of ground dwelling predators. Direct effects of adjacent AES habitats on assemblages in oilseed rape fields however were limited and only visible in functional traits of carabid beetle assemblages. Adjacent AES habitats doubled the proportion of predatory carabid beetles indicating a beneficial role for pest control. My results show that pest control potentials are largest close to the field edges and beneficial effects are comparably short ranged. Chapter VII: The effects of AES habitats on pest control in adjacent cereal fields Whether distance functions and potential effects of AES habitats are universal across crops is unknown. Therefore, I assessed distance functions of predators, pests, predation rates and yields after crop rotation in winter cereals using the same study design as in the previous year. Resulting distance functions were not uniform and differed from those found in oilseed rape in the previous year, indicating that the interactions between certain adjacent habitats vary with habitat and crop types. Distance functions of cereal-leaf beetles (important cereal pests) and parasitoid wasps were moreover modulated by semi-natural habitat proportion in the surrounding landscapes. Field edges buffered assemblage changes in carabid beetle assemblages over crop rotation confirming their important function as refuges for natural enemies. My results emphasize the beneficial role of field edges for pest control potentials. These findings back the calls for smaller field sizes and more diverse, more heterogeneously structured agricultural landscapes. Chapter VIII: General Discussion Countering biodiversity loss and ensuring ecosystem service provision in agricultural landscapes is intricate and requires strategic planning and restructuring of these landscapes. I showed that agricultural landscapes could benefit maximally from (i) a mixture of AES habitats and semi-natural habitats to support high levels of overall biodiversity and from (ii) smaller continuously managed agricultural areas (i.e. smaller field sizes or the insertion of AES elements within large fields) to maximize natural pest control potentials in crop fields. I propose a mosaic of younger AES habitats and semi-natural habitats to support ecosystem service providers and increase edge density for ecosystem service spillover into adjacent crops. The optimal extent and density of this network as well as the location in which AES and semi-natural habitats interact most beneficially with adjacent crops need further investigation. My results provide a further step towards more sustainable agricultural landscapes that simultaneously allow biodiversity to persist and maintain agricultural production under the framework of ecological intensification.}, subject = {{\"O}kologie}, language = {en} } @phdthesis{Amatobi2022, author = {Amatobi, Kelechi Michael}, title = {Circadian clocks determine transport and membrane lipid oscillation in \(Drosophila\) hemolymph in complex interactions between nutrient-type, photic conditions and feeding behaviour}, doi = {10.25972/OPUS-24446}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244462}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The interaction between circadian clocks and metabolism is of increasing interest, since clock dysfunction often correlates with metabolic pathologies. Many research articles have been published analysing the impact of factors such as circadian clock, light, feeding time and diet-type on energy homeostasis in various tissues/organs of organisms with most of the findings done in mammals. Little is known about the impact of circadian clock and the above-mentioned factors on circulating lipids, especially the transport form of lipids - diacylglycerol (DG) and membrane lipids such as phosphatidylethanolamine (PE) and phosphatidylcholine (PC) in the Drosophila hemolymph. The fruit fly Drosophila is a prime model organism in circadian, behaviour and metabolism research. To study the role of circadian clock and behaviour in metabolism, we performed an extensive comparative hemolymph lipid (diacylglycerol: DG, phosphatidylethanolamine: PE, phosphatidylcholine: PC) analysis using ultra performance liquid chromatography coupled to time-of-flight mass spectrometry (UPLC-MS) between wild-type flies (WTCS) and clock disrupted mutants (per01). In addition, clock controlled food intake- feeding behaviour was investigated. Time-dependent variation of transport (DG) and membrane lipids (PE and PC) were not rhythmic in WTCS under constant darkness and in per01 under LD, suggesting an impact of light and clock genes on daily lipid oscillations. Day-time and night-time restriction of food led to comparable lipid profiles, suggesting that lipid oscillations are not exclusively entrained by feeding but rather are endogenously regulated. Ultradian oscillations in lipid levels in WTCS under LD were masked by digested fatty acids since lipid levels peaked more robustly at the beginning and end of light phase when flies were fed a lipid- and protein-free diet. These results suggest that metabolite (DG, PE and PC) oscillation is influenced by complex interactions between nutrient-type, photic conditions, circadian clock and feeding time. In conclusion, the results of this thesis suggest that circadian clocks determine transport and membrane lipid oscillation in Drosophila hemolymph in complex interactions between nutrient-type, photic conditions and feeding behaviour.}, subject = {Pharmaceutische Biologie}, language = {en} } @phdthesis{Hische2022, author = {Hische, Sophie Luisa Hella}, title = {Untersuchung des Therapieprinzips "Damage Control Orthopaedics" an Verletzungen der oberen Extremit{\"a}t bei polytraumatisierten Patienten}, doi = {10.25972/OPUS-24453}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244539}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die vorliegende Arbeit untersucht die Therapiekonzepte „early total care" (ETC) und „damage control orthopaedics" (DCO) bei der Behandlung 90 polytraumatisierter Patienten mit Verletzungen an der oberen Extremit{\"a}t in der Universit{\"a}tsklinik W{\"u}rzburg. Nach dem „first hit" im Rahmen des Polytraumas kann der Organismus und das Immunsystem durch eine aufwendige Operation im Sinne eines „second hit" {\"u}berfordert werden. Ziel des DCO ist es den „second hit" zu minimieren, indem initial nur die notwendigsten Behandlungen durchgef{\"u}hrt werden und keine vollst{\"a}ndige Ausversorgung entsprechend ETC durchgef{\"u}hrt wird. Es werden Kriterien herausgearbeitet, welche relevant f{\"u}r die initiale Therapieentscheidung sind. Liegen eine hohe Verletzungsschwere (ISS), Kreislaufkomplikationen und eine niedrige {\"U}berlebensprognose nach dem RISC II sowie schwere begleitende Kopf-, Abdomen-, Becken- oder Wirbels{\"a}ulenverletzungen vor, werden die Verletzungen an der oberen Extremit{\"a}t nach DCO therapiert. Zudem wird f{\"u}r komplexe Verletzungen der oberen Extremit{\"a}t mit Gelenkbeteiligung, Bandsch{\"a}den oder schwerem Weichteilschaden, welche zeitaufwendige und planungsintensive Operationsverfahren bed{\"u}rfen, die DCO-Strategie favorisiert. Wenn die notwendige Lagerung des Patienten auf dem Operationstisch f{\"u}r die Ausversorgung der Verletzung an der oberen Extremit{\"a}t initial m{\"o}glich ist, wird die obere Extremit{\"a}tenverletzung nach ETC therapiert, insbesondere wenn eine schwere Verletzung an der oberen Extremit{\"a}t vorliegt. In der ETC-Kohorte ist kein Patient verstorben. Das schlechtere Outcome in der DCO-Kohorte liegt vor allem an der initial h{\"o}heren Verletzungsschwere. Auf Grund der besseren tats{\"a}chlichen als erwarteten Mortalit{\"a}t kann DCO als eine erfolgreiche Therapiestrategie bei schwerverletzten Patienten angesehen werden. Jedoch kann die vorliegende Arbeit keinen Nachteil f{\"u}r die Patienten durch die ETC-Behandlung feststellen.}, subject = {Polytrauma}, language = {de} } @phdthesis{Hartmann2022, author = {Hartmann, Tim}, title = {{\"U}ber die Rolle der Neuroinflammation bei Entstehung und Progression der Demenz vom Alzheimer-Typ}, doi = {10.25972/OPUS-24532}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245326}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die vorliegende Studie bringt neue Erkenntnisse bez{\"u}glich der Rolle und Ver-teilung der Mikroglia und der eingewanderten Monozyten im Verlauf der Alz-heimer Erkrankung in postmortem Gehirnen. Im Gegensatz zu Studien an Tiermodellen konnten wir in unserer Kohorte eine nur sehr geringe Beteili-gung myeloischer Monozyten an der AD Pathologie beobachten, so dass man annehmen kann, dass bei Menschen die Immunantwort des Gehirns haupt-s{\"a}chlich von den hirneigenen Mikrogliazellen getragen wird. Dies wurde an humanem postmortem Hirngewebe bis zu diesem Zeitpunkt noch nicht unter-sucht. Zudem konnte gezeigt werden, dass die vulnerablen, fr{\"u}h von Tangles und Plaques betroffenen Hirnregionen auch eine fr{\"u}he Mikrogliareaktion aufwei-sen und insbesondere von proinflammatorischen Zellen besiedelt werden und dass die Reaktion in manchen Regionen im Verlauf zunimmt, w{\"a}hrend in an-deren eine Abflachung oder sogar Abnahme beobachtet wird.}, subject = {Alzheimerkrankheit}, language = {de} } @phdthesis{Dechant2022, author = {Dechant, Moritz Thomas}, title = {Synthese und Struktur-Eigenschaftsbeziehungen neuer Phthalocyanin-Sternmesogene - Ein neues Design f{\"u}r organische, fl{\"u}ssigkristalline Photovoltaikmaterialien}, doi = {10.25972/OPUS-23888}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238888}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Es wurde eine Vielzahl neuer, fl{\"u}ssigkristalliner Phthalocyanin-Sternmesogene synthetisiert. Die Struktur-Eigenschaftsbeziehungen und die thermotropen Eigenschaften neuer Phthalocyanin-Sternmesogene mit Freiraum sowie von sterisch {\"u}berfrachteten Verbindungen wurden insbesondere hinsichtlich der Freiraumf{\"u}llung untersucht. Diesbez{\"u}glich wurde ein neuer supramolekularer, freiraumf{\"u}llender "Klick-Prozess" zwischen einem Molek{\"u}l mit Freiraum und einem sterisch {\"u}berfrachteten Molek{\"u}l mit vier Fullerenen beobachtet. Die photophysikalischen Eigenschaften wurden zudem insbesondere im Hinblick auf die Anwendung f{\"u}r die Organische Photovoltaik untersucht.}, subject = {Phthalocyanin}, language = {de} } @phdthesis{Vietz2022, author = {Vietz, Melanie Sabrina}, title = {Pr{\"a}vention von Angsterkrankungen: Etablierung und Validierung des Kognitiven Angstsensitivit{\"a}tstrainings (KAST) - Deutsche Version}, doi = {10.25972/OPUS-22312}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-223122}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Angsterkrankungen stellen mit einer 12-Monats-Pr{\"a}valenz von 14\% die h{\"a}ufigsten psychischen Erkrankungen in der westlichen Gesellschaft dar. Angesichts der hohen querschnittlichen wie sequentiellen Komorbidit{\"a}t von Angsterkrankungen, der ausgepr{\"a}gten individuellen Einschr{\"a}nkungen sowie der hohen {\"o}konomischen Belastung f{\"u}r das Gesundheitssystem ist neben therapeutischen Behandlungsans{\"a}tzen die Entwicklung von kurzzeitigen, kosteng{\"u}nstigen und leicht zug{\"a}nglichen Pr{\"a}ventionsmaßnahmen von großer Bedeutung und steht zunehmend im Fokus des gesundheitspolitischen Interesses, um die Inzidenz von Angsterkrankungen zu reduzieren. Voraussetzung f{\"u}r die Entwicklung von gezielten und damit den effektivsten Pr{\"a}ventionsmaßnahmen sind valide Risikofaktoren, die die Entstehung von Angsterkrankungen beg{\"u}nstigen. Ein Konstrukt, das in der Literatur als subklinisches Symptom in Form einer kognitiven Vulnerabilit{\"a}t f{\"u}r Angsterkrankungen und damit als Risikofaktor angesehen wird, ist die sogenannte Angstsensitivit{\"a}t (AS). AS umfasst die individuelle Tendenz, angstbezogene k{\"o}rperliche Symptome generell als bedrohlich einzustufen und mit aversiven Konsequenzen zu assoziieren. Das Ziel der vorliegenden Arbeit war daher die Etablierung und Validierung eines Pr{\"a}ventionsprogramms zur Reduktion der AS an einer nicht-klinischen Stichprobe von 100 Probanden (18-30 Jahre) mit einer erh{\"o}hten AS (Anxiety Sensitivity Index [ASI-3] ≥17) sowie die Rekrutierung von 100 alters- und geschlechtsangeglichenen Probanden mit niedriger Angstsensitivit{\"a}t (ASI-3 <17). In einem randomisiert-kontrollierten Studiendesign durchliefen die Probanden mit hoher AS entweder das {\"u}ber f{\"u}nf Wochen angelegte „Kognitive Angstsensitivit{\"a}tstraining" (KAST) als erste deutschsprachige {\"U}bersetzung des Computer-basierten „Cognitive Anxiety Sensitivity Treatment" (CAST) von Schmidt et al. (2014) oder wurden der Wartelisten-Kontrollgruppe zugeteilt. Das KAST Training bestand aus einer einmaligen Vermittlung kognitiv-behavioraler Psychoedukation zum Thema Stress und Anspannung sowie deren Auswirkungen auf den K{\"o}rper und der Anleitung von zwei interozeptiven Expositions{\"u}bungen (‚Strohhalm-Atmung' und ‚Hyperventilation'), die {\"u}ber den anschließenden Zeitraum von f{\"u}nf Wochen in Form von Hausaufgaben wiederholt wurden. Es konnte gezeigt werden, dass die Teilnehmer des KAST-Programms nach Beendigung des Trainings (T1) eine signifikant niedrigere AS-Auspr{\"a}gung im Vergleich zur Wartelisten-Kontrollgruppe aufwiesen und diese Reduktion auch {\"u}ber den Katamnese-Zeitraum von sechs Monaten (T2) stabil blieb. Erg{\"a}nzend wurde auch die Targetierbarkeit weiterer intermedi{\"a}rer Risikomarker wie der Trennungsangst (TA), des Index der kardialen Sensitivit{\"a}t sowie der Herzratenvariabilit{\"a}t (HRV) untersucht, die jedoch nicht durch das KAST-Training direkt ver{\"a}ndert werden konnten. Im Vergleich der Subgruppen von Probanden mit hoher AS und gleichzeitig hoher TA (Adult Separation Anxiety Questionnaire [ASA-27] ≥22) und Probanden mit hoher AS, aber niedriger TA (ASA-27 <22) zeigte sich, dass die AS-TA-Hochrisikogruppe ebenfalls gut von der KAST-Intervention profitieren und eine signifikante Reduktion der AS erzielen konnte, indem sie sich bei T1 dem Niveau der Gruppe mit niedriger TA anglich. Zudem korrelierte die prozentuale Ver{\"a}nderung der Einstiegswerte der inneren Anspannung w{\"a}hrend der Strohhalm-Atmungs{\"u}bung positiv mit der prozentualen Ver{\"a}nderung der dimensionalen TA bei T1. Zusammenfassend weisen die Ergebnisse der vorliegenden Arbeit erstmalig auf die Wirksamkeit der deutschsprachigen {\"U}bersetzung des CAST-Programms (Schmidt et al., 2014), eines Computer-basierten, und damit leicht zu implementierenden sowie kosteng{\"u}nstigen Programms, in Bezug auf die Reduktion der AS sowie indirekt der TA hin und k{\"o}nnen damit zur indizierten und demnach besonders effektiven Pr{\"a}vention von Angsterkrankungen in Hochrisikogruppen beitragen.}, subject = {Angstst{\"o}rung}, language = {de} } @phdthesis{Pies2022, author = {Pies, Jennifer}, title = {Die Funktion des Nervus facialis - Bedeutung f{\"u}r die Lebensqualit{\"a}t nach Operationen von Vestibularisschwannomen}, doi = {10.25972/OPUS-23548}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235481}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Im Rahmen der vorliegenden Arbeit wurden Daten von Patienten ausgewertet, die an einem Vestibularisschwannom erkrankt sind. Dabei wurde der Einfluss einer Facialisparese auf die Lebensqualit{\"a}t untersucht. Die Auswertung der Daten zeigte statistisch signifikante Zusammenh{\"a}nge zwischen verschiedenen Dom{\"a}nen der Lebensqualit{\"a}t und einer postoperativen Facialisparese.}, subject = {Vestibularisschwannom}, language = {de} } @phdthesis{Schindler2022, author = {Schindler, Dorothee}, title = {Water Oxidation with Multinuclear Ruthenium Catalysts}, doi = {10.25972/OPUS-23309}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-233093}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {In terms of the need of environmentally benign renewable and storable energy sources, splitting of water into hydrogen and oxygen by using sunlight is a promising approach. Hereby, water oxidation catalysts (WOCs) are required to perform the water oxidation comprising the transfer of four electrons to provide the reducing equivalents for producing hydrogen. The class of Ru(bda) (bda = 2,2'-bipyridine-6,6'-dicarboxylate) catalysts has proven to be efficient for this reaction. In this thesis, ligand exchange processes in Ru(bda) complexes have been analyzed and the formation of multinuclear macrocyclic WOCs was studied. Based on the knowledge acquired by these studies, new multinuclear cyclic Ru(bda) complexes have been synthesized and their catalytic efficiencies in homogeneous water oxidation have been investigated. Going one step further for setting up functional devices, molecular WOCs have been immobilized on conducting or semiconducting supporting materials. Direct anchoring on carbon nanotubes generated a promising materials for further applications.}, subject = {Rutheniumkomplexe}, language = {en} } @misc{OPUS4-25817, title = {einBlick - Ausgabe 07 - 22. Februar 2022}, series = {einBlick}, volume = {07/2022}, journal = {einBlick}, organization = {Julius-Maximilians-Universit{\"a}t W{\"u}rzburg}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258174}, year = {2022}, abstract = {Nachrichten aus der Julius-Maximilians-Universit{\"a}t W{\"u}rzburg}, subject = {Universit{\"a}t}, language = {de} } @phdthesis{DanglgebStimmer2022, author = {Dangl [geb. Stimmer], Magdalena}, title = {Die Wirksamkeit von Schienentherapie und okklusalen Einschleifmaßnahmen unter Ber{\"u}cksichtigung des Chronifizierungsgrades Craniomandibul{\"a}rer Dysfunktionen: Eine Systematische {\"U}bersichtsarbeit mit Metaanalyse}, doi = {10.25972/OPUS-25675}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256755}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Hintergrund: Die fehlende Diagnostik des patientInnenindividuellen CMD-Schmerzchronifizierungsgrades k{\"o}nnte Grund f{\"u}r die Heterogenit{\"a}t der Studienergebnisse zur Effektivit{\"a}t von Schienentherapie und okklusalen Einschleifmaßnahmen sein. Ziele: Dieser Systematische Review mit Metaanalyse hat als Ziel, die Effektivit{\"a}t von Schienentherapie und okklusalen Einschleifmaßnahmen bei der Behandlung von CMD unter besonderer Ber{\"u}cksichtigung des Grades der Schmerzchronifizierung zu untersuchen. Literaturquellen: Die Datenbanken Pubmed/MEDLINE, EMBASE, Cochrane Library, Livivo, OpenGrey, drks.de, Clinicaltrials.gov., sowie zus{\"a}tzliche nicht gelistete Literatur wurden hierzu durchsucht. Auswahlkriterien: Analysiert wurden randomisierte klinische Studien, welche erwachsene PatientInnen mit einer schmerzhaften CMD untersuchten, die mit einer Okklusionsschiene oder okklusalen Einschleifmaßnahmen in jeglicher Kombination behandelt wurden. Die Studien wurden nach Hinweisen untersucht, die vermuten ließen, dass die ProbandInnen unter einer chronifizierten dysfunktionalen CMD Schmerzen litten. Anschließend wurde die Effektivit{\"a}t der Interventionen im Hinblick auf den erfassten bzw. vermuteten Chronifizierungsgrad differenziert betrachtet. Die Effektivit{\"a}t wurde bzgl. der folgenden Messparameter untersucht: aktuelle Schmerzintensit{\"a}t in Ruhe, maximal aktive Kiefer{\"o}ffnungskapazit{\"a}t, Kiefergelenkger{\"a}usche, Palpationsschmerzen aus der Kaumuskulatur, Depressivit{\"a}t und somatoforme Beschwerden. Studienbewertung: Nachdem die eingeschlossenen Studien ausgewertet, in ihrer Qualit{\"a}t bewertet (Risk of Bias-Tool des Cochrane-Instituts) und die Daten extrahiert worden waren, wurde eine Metaanalyse mithilfe des Review Managers (RevMan 5.3) des Cochrane Instituts durchgef{\"u}hrt. Ergebnisse: ProbandInnen mit funktionalen Schmerzen nach den hier definierten Kriterien erfuhren bis zu 6 Monate nach Behandlungsbeginn eine statistisch signifikant st{\"a}rkere Schmerzreduktion (p<0,00001) sowie niedrigere Werte der somatoformen Beschwerden (p=0,01) und Depression-Scores (p=0,002) als Probanden mit dysfunktionalen Schmerzen. Dagegen verbesserte sich die Kiefer{\"o}ffnungskapazit{\"a}t in dieser Subgruppe nicht statistisch signifikant mehr (p=0,40). Im kurzfristigen Zeitraum von bis zu 6 Monaten konnte die Okklusionsschiene verglichen mit einer Placebo-Schiene st{\"a}rker CMD-Schmerzen senken (p=0,0002), wohingegen der Effektivit{\"a}tsunterschied der Messparameter Kiefer{\"o}ffnungskapazit{\"a}t und Kiefergelenkger{\"a}usche nicht statistisch signifikant war. Im Vergleich zu keiner Behandlung war die Okklusionsschiene im Zeitraum bis zu 6 Monaten statistisch signifikant effektiver in der Schmerzreduktion (p<0,00001); 6 bis 12 Monate nach Behandlungsbeginn war keine signifikant bessere Effektivit{\"a}t in der Schmerzreduktion zu verzeichnen (p=0,07). Die maximale Kiefer{\"o}ffnungskapazit{\"a}t zeigte in diesem Vergleich kein statistisch signifikantes Ergebnis im kurzfristigen Zeitraum. Die Schmerzreduktion im kurzfristigen Zeitraum {\"a}hnelte derer anderer aktiver Interventionen. Als Kointervention bringt die Schienentherapie in keinem der untersuchten Endpunkte und Zeitr{\"a}ume einen statistisch signifikanten Mehrwert mit sich. Eine erh{\"o}hte Vertikaldimension k{\"o}nnte die Effektivit{\"a}t der Okklusionsschiene verbessern. Ansonsten ist die Effektivit{\"a}t unterschiedlicher Okklusionsschienen vergleichbar, unter Ber{\"u}cksichtigung folgender Beobachtungen: eine ARS senkt die Schmerzen einer arthrogenen CMD (p=0,001) und eine Stabilisierungsschiene die Schmerzen einer myogenen oder gemischten CMD (p<0,00001) effektiver als keine Behandlung. Intraorale Adjustierungen eine Verbesserung der Schmerzsymptomatik erzielen (p=0,01). Die langfristige Effektivit{\"a}t der Interventionen konnte aufgrund der geringen Datenlage nicht ausreichend untersucht werden. Registrierungsnummer der Review bei PROSPERO: CRD42019123169.}, subject = {Gesichtsschmerz}, language = {de} } @phdthesis{Feisel2022, author = {Feisel, Sarah}, title = {Die Begr{\"u}ndung der Keimblatttheorie durch Christian Heinrich Pander 1817 in W{\"u}rzburg: Der Weg naturphilosophisch gepr{\"a}gter Embryologieforschung zur rationalen Wissenschaft}, doi = {10.25972/OPUS-25681}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256811}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Christian Heinrich Pander begr{\"u}ndete 1817 in W{\"u}rzburg die Keimblatttheorie. Zu seinen Erkenntnissen gelangte er durch Studien am H{\"u}hnerembryo. Beim Erlernen und bei der Durchf{\"u}hrung der wissenschaftlichen Methodik mit dem Mikroskop unterst{\"u}tzte ihn der W{\"u}rzburger Professor und Naturforscher Ignaz D{\"o}llinger maßgeblich. Neben der Aufarbeitung der wissenschaftlichen Methodik und den hieraus neu gewonnenen Erkenntnissen besch{\"a}ftigt sich diese Arbeit ebenso mit der Aufarbeitung naturphilosophischer Motive in den naturwissenschafts-historischen Kontext der Embryologie-Geschichte des fr{\"u}hen 19. Jahrhunderts gesetzt.}, subject = {Embryologie}, language = {de} } @phdthesis{Turkin2022, author = {Turkin, Arthur}, title = {Vom Monomer zum Polymer: Iterative Synthese und optische Spektroskopie von Squarain-Oligomeren}, doi = {10.25972/OPUS-25795}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257950}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Mittels einer Schutzgruppenstrategie wurden Squarain-basierte monodisperse Oligomere synthetisiert. Die l{\"o}sungsmittelabh{\"a}ngigen Konformationen (Random Coil vs. Helix) wie auch der Faltungsprozess der Homooligomere wurden mittels optischer Spektroskopie, verschiedener NMR-Experimenten, Kleinwinkelneutronenstreuungsexperimenten sowie quantenchemischen Berechnungen n{\"a}her beleuchtet. Die optisch-spektroskopischen Beobachtungen wurden mithilfe der Exzitonenkopplungstheorie und einer Orientierungs- und Winkelabh{\"a}ngigkeit der {\"U}bergangsdipolmomente der Oligomere erkl{\"a}rt. Der hohe Windungsabstand der helikalen Konformation f{\"u}hrt zu einer Interkalation von L{\"o}sungsmittel, wodurch eine Art Klathrat gebildet wird. Zus{\"a}tzlich wurden mittels eines Frenkel-Exzitonenmodells die Absorptions- und Fluoreszenzspektren modelliert. Es konnten die Exzitonendelokalisationsl{\"a}ngen abgesch{\"a}tzt und die Auswirkung der energetischen und strukturellen Unordnungen auf die Absorptions- und Fluoreszenzspektren bestimmt werden. Die Absorptionsspektren werden vorwiegend durch strukturelle Unordnungen verbreitert, die Fluoreszenzspektren dagegen von energetischen {\"U}bergangsenergieabweichungen. Weiterhin wurden auch alternierende Squarain-Cooligomere synthetisiert und mittels optischer Spektroskopie untersucht. Es wurde, abh{\"a}ngig von dem gew{\"a}hlten L{\"o}sungsmittel, eine Verschiebung der Hauptbande beobachtet, was durch einen Random Coil vs. helikale-/schlaufenartige Konformation erkl{\"a}rt wird. Gest{\"u}tzt wurde dies mittels quantenchemischen Berechnungen der jeweiligen Konformationen. Abschließend wurden alternierende Squarain-Copolymere synthetisiert, in verschiedenen Gr{\"o}ßen aufgetrennt und mittels optischer Spektroskopie untersucht. Mittels EEI2D-Experimenten wurde die Exzitonendynamik in Abh{\"a}ngigkeit von der Kettenl{\"a}nge eingehender untersucht. Hierbei wird eine steigende, aber relativ abnehmende Koh{\"a}renzl{\"a}nge bestimmt, die Auswirkungen auf die Exzitonendynamik hat. Der Exzitonentransport weist erst wellenf{\"o}rmiges und dann subdiffuses Verhalten auf.}, subject = {Squarain}, language = {de} } @phdthesis{Vellmer2022, author = {Vellmer, Tim}, title = {New insights into the histone variant H2A.Z incorporation pathway in \(Trypanosoma\) \(brucei\)}, doi = {10.25972/OPUS-25796}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257960}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The histone variant H2A.Z is a key player in transcription regulation in eukaryotes. Histone acetylations by the NuA4/TIP60 complex are required to enable proper incorporation of the histone variant and to promote the recruitment of other complexes and proteins required for transcription initiation. The second key player in H2A.Z-mediated transcription is the chromatin remodelling complex SWR1, which replaces the canonical histone H2A with its variant. By the time this project started little was known about H2A.Z in the unicellular parasite Trypanosoma brucei. Like in other eukaryotes H2A.Z was exclusively found in the transcription start sites of the polycistronic transcription units where it keeps the chromatin in an open conformation to enable RNA-polymerase II-mediated transcription. Previous studies showed the variant colocalizing with an acetylation of lysine on histone H4 and a methylation of lysine 4 on histone H3. Data indicated that HAT2 is linked to H2A.Z since it is required for acetylation of lyinse 10 on histone H4. A SWR1-like complex and a complex homologous to the NuA4/TIP60 could not be identified yet. This study aimed at identifying a SWR1-like remodelling complex in T. brucei and at identifying a protein complex orthologous to NuA4/TIP60 as well as at answering the question whether HAT2 is part of this complex or not. To this end, I performed multiple mass spectrometry-coupled co-Immunoprecipitation assays with potential subunits of a SWR1 complex, HAT2 and a putative homolog of a NuA4/TIP60 subunit. In the course of these experiments, I was able to identify the TbSWR1 complex. Subsequent cell fractionation and chromatin immunoprecipitation-coupled sequencing analysis experiments confirmed, that this complex is responsible for the incorporation of the histone variant H2A.Z in T. brucei. In addition to this chromatin remodelling complex, I was also able to identify two histone acetyltransferase complexes assembled around HAT1 and HAT2. In the course of my study data were published by the research group of Nicolai Siegel that identified the histone acetyltransferase HAT2 as being responsible for histone H4 acetylation, in preparation to promote H2A.Z incorporation. The data also indicated that HAT1 is responsible for acetylation of H2A.Z. According to the literature, this acetylation is required for proper transcription initiation. Experimental data generated in this study indicated, that H2A.Z and therefore TbSWR1 is involved in the DNA double strand break response of T. brucei. The identification of the specific complex composition of all three complexes provided some hints about how they could interact with each other in the course of transcription regulation and the DNA double strand break response. A proximity labelling approach performed with one of the subunits of the TbSWR1 complex identified multiple transcription factors, PTM writers and proteins potentially involved in chromatin maintenance. Overall, this work will provide some interesting insights about the composition of the complexes involved in H2A.Z incorporation in T. brucei. Furthermore, it is providing valuable information to set up experiments that could shed some light on RNA-polymerase II-mediated transcription and chromatin remodelling in T. brucei in particular and Kinetoplastids in general.}, subject = {Chromatinremodelling}, language = {en} } @phdthesis{vonBosse2022, author = {von Bosse, Felix}, title = {Risikofaktoren der venoarteriellen extrakorporalen Membranoxygenierung bei Post-Kardiotomie-Patienten}, doi = {10.25972/OPUS-25819}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258198}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Die extrakorporale Membranoxygenierung ist ein seit Jahrzehnten etabliertes Verfahren, Patienten trotz kardialem und/oder pulmonalem Versagen ein zeitbegrenztes {\"U}berleben zu erm{\"o}glichen. Obgleich sich an den Grundz{\"u}gen der Herangehensweise bis heute wenig ver{\"a}ndert hat, konnte diese Hochrisikotherapie mithilfe der Entwicklung blutschonenderer Materialien und der Verwendung verbesserter Pumpen und Oxygenatoren zunehmend effizienter gestaltet werden. Durch eine {\"U}berlebensanalyse aller ECMO-Patienten der Datenbank der Klinik f{\"u}r Tho-rax-, Herz- und Thorakale Gef{\"a}ßchirurgie des Universit{\"a}tsklinikums W{\"u}rzburg zwischen 2015 und 2018 (172 F{\"a}lle) sollten unabh{\"a}ngige Risikofaktoren f{\"u}r ein negatives Outcome der Therapie identifiziert werden. Insbesondere den Laborparametern w{\"a}hrend der ersten 72 Stunden am System galt hierbei ein besonderes Augenmerk, aber auch Vorerkrankun-gen, Komplikationen, Substitutionen w{\"a}hrend der Therapie und weitere Parameter wurden f{\"u}r jeden Patienten individuell ermittelt und tabellarisch festgehalten. Insgesamt verstarben davon 125 Patienten (72,7\%), 47 Patienten (27,3\%) {\"u}berlebten und konnten entlassen werden. Bei 24 der 125 verstorbenen Patienten (14\%) konnte zwar ein Weaning vom System erfolgreich durchgef{\"u}hrt werden (>24h), sie verstarben jedoch w{\"a}hrend des anschließenden station{\"a}ren Aufenthaltes. Bei den pr{\"a}insertionell erhobenen Parametern waren der BMI und der Euroscore II bei verstorbenen Patienten signifikant h{\"o}her, ebenso wie die Cross-Clamp-Zeit und der SO-FA-Score. F{\"u}r die Laborwerte an ECMO ergaben sich f{\"u}r den Serumlaktatspiegel und die Throm-bozytenanzahl der Patienten die signifikantesten Unterschiede. Auch andere Laborparame-ter erwiesen sich in beiden Gruppen als signifikant unterschiedlich: Insbesondere der Quick Wert der {\"u}berlebenden Patienten war zu Beginn signifikant h{\"o}her. Auch der Fibri-nogenspiegel der Gruppe der {\"u}berlebenden Patienten lag ab der 12 Stunden Marke signi-fikant h{\"o}her. Verstorbene Patienten erhielten mehr Blutpr{\"a}parate als {\"U}berlebende. Außerdem f{\"u}hrte ein dialysepflichtiges Nierenversagen im Laufe der Therapie zu signifikant schlechterem Out-come. Wider Erwarten waren w{\"a}hrend der Therapie auftretende Blutungskomplikationen nicht mit schlechterem Outcome assoziiert. Jedoch konnte bei Auftritt von Thromben im Sys-tem, die einen Austausch des Oxygenators/ECMO-Systems n{\"o}tig machten, sowie Magen-Darm-Isch{\"a}mien und Kompartmentsyndrom ein klarer {\"U}berlebensnachteil erfasst werden. Abschließend ließ sich mittels multivariater logistischer Regression zeigen, dass der SO-FA-Score, der Serumlaktatspiegel und die Thrombozytenanzahl sowie eine adjuvante I-ABP Implantation und der Bedarf einer Nierenersatztherapie den gr{\"o}ßten Einfluss auf das {\"U}berleben der Patienten hatten.}, subject = {ECMO}, language = {de} } @phdthesis{Reis2022, author = {Reis, Felix}, title = {Realization and Spectroscopy of the Quantum Spin Hall Insulator Bismuthene on Silicon Carbide}, doi = {10.25972/OPUS-25825}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258250}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Topological matter is one of the most vibrant research fields of contemporary solid state physics since the theoretical prediction of the quantum spin Hall effect in graphene in 2005. Quantum spin Hall insulators possess a vanishing bulk conductivity but symmetry-protected, helical edge states that give rise to dissipationless charge transport. The experimental verification of this exotic state of matter in 2007 lead to a boost of research activity in this field, inspired by possible ground-breaking future applications. However, the use of the quantum spin Hall materials available to date is limited to cryogenic temperatures owing to their comparably small bulk band gaps. In this thesis, we follow a novel approach to realize a quantum spin Hall material with a large energy gap and epitaxially grow bismuthene, i.e., Bi atoms adopting a honeycomb lattice, in a \((\sqrt{3}\times\sqrt{3})\) reconstruction on the semiconductor SiC(0001). In this way, we profit both from the honeycomb symmetry as well as the large spin-orbit coupling of Bi, which, in combination, give rise to a topologically non-trivial band gap on the order of one electronvolt. An in-depth theoretical analysis demonstrates that the covalent bond between the Si and Bi atoms is not only stabilizing the Bi film but is pivotal to attain the quantum spin Hall phase. The preparation of high-quality, unreconstructed SiC(0001) substrates sets the basis for the formation of bismuthene and requires an extensive procedure in ultra-pure dry H\(_2\) gas. Scanning tunneling microscopy measurements unveil the (\(1\times1\)) surface periodicity and smooth terrace planes, which are suitable for the growth of single Bi layers by means of molecular beam epitaxy. The chemical configuration of the resulting Bi film and its oxidation upon exposure to ambient atmosphere are inspected with X-ray photoelectron spectroscopy. Angle-resolved photoelectron spectroscopy reveals the excellent agreement of probed and calculated band structure. In particular, it evidences a characteristic Rashba-splitting of the valence bands at the K point. Scanning tunneling spectroscopy probes signatures of this splitting, as well, and allows to determine the full band gap with a magnitude of \(E_\text{gap}\approx0.8\,\text{eV}\). Constant-current images and local-density-of-state maps confirm the presence of a planar honeycomb lattice, which forms several domains due to different, yet equivalent, nucleation sites of the (\(\sqrt{3}\times\sqrt{3}\))-Bi reconstruction. Differential conductivity measurements demonstrate that bismuthene edge states evolve at atomic steps of the SiC substrate. The probed, metallic local density of states is in agreement with the density of states expected from the edge state's energy dispersion found in density functional theory calculations - besides a pronounced dip at the Fermi level. By means of temperature- and energy-dependent tunneling spectroscopy it is shown that the spectral properties of this suppressed density of states are successfully captured in the framework of the Tomonaga-Luttinger liquid theory and most likely originate from enhanced electronic correlations in the edge channel.}, subject = {Zweidimensionales Material}, language = {en} } @masterthesis{Busch2022, type = {Bachelor Thesis}, author = {Busch, Marlene Corinna}, title = {Developing a virtual Control Room for future satellite missions}, doi = {10.25972/OPUS-25826}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258261}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {This thesis deals with the first part of a larger project that follows the ultimate goal of implementing a software tool that creates a Mission Control Room in Virtual Reality. The software is to be used for the operation of spacecrafts and is specially developed for the unique real-time requirements of unmanned satellite missions. Beginning from launch, throughout the whole mission up to the recovery or disposal of the satellite, all systems need to be monitored and controlled in continuous intervals, to ensure the mission's success. Mission Operation is an essential part of every space mission and has been undertaken for decades. Recent technological advancements in the realm of immersive technologies pave the way for innovative methods to operate spacecrafts. Virtual Reality has the capability to resolve the physical constraints set by traditional Mission Control Rooms and thereby delivers novel opportunities. The paper highlights underlying theoretical aspects of Virtual Reality, Mission Control and IP Communication. However, the focus lies upon the practical part of this thesis which revolves around the first steps of the implementation of the virtual Mission Control Room in the Unity Game Engine. Overall, this paper serves as a demonstration of Virtual Reality technology and shows its possibilities with respect to the operation of spacecrafts.}, subject = {Control room}, language = {en} } @phdthesis{Lasway2022, author = {Lasway, Julius Vincent}, title = {Impact of human land use on bee diversity and plant-pollinator interactions in Tanzania savannah ecosystems}, doi = {10.25972/OPUS-25772}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257726}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {One of the pronounced global challenges facing ecologists is how to feed the current growing human population while sustaining biodiversity and ecosystem services. To shed light on this, I investigated the impact of human land use on bee diversity and plant-pollinator interactions in Tanzania Savannah ecosystems. The thesis comprises the following chapters: Chapter I: General Introduction This chapter provides the background information including the study objectives and hypotheses. It highlights the ecological importance of bees and the main threats facing bee pollinators with a focus on two land-use practices namely livestock grazing and agriculture. It also highlights the diversity and global distribution of bees. It further introduces the tropical savannah ecosystem, its climate, and vegetation characteristics and explains spectacular megafauna species of the system that form centers of wildlife tourism and inadequacy knowledge on pollinators diversity of the system. Finally, this chapter describes the study methodology including, the description of the study area, study design, and data collection. Chapter II: Positive effects of low livestock grazing intensity on East African bee assemblages mediated by increases in floral resources The impact of livestock grazing intensity on bee assemblage has been subjected to research over decades. Moreover, most of these studies have been conducted in temperate Europe and America leaving the huge tropical savannah of East Africa less studied. Using sweep netting and pan traps, a total of 183 species (from 2,691 individuals) representing 55 genera and five families were collected from 24 study sites representing three levels of livestock grazing intensity in savannah ecosystem of northern Tanzania. Results have shown that moderate livestock grazing slightly increased bee species richness. However, high livestock grazing intensity led to a strong decline. Besides, results revealed a unimodal distribution pattern of bee species richness and mean annual temperature. It was also found that the effect of livestock grazing and environmental temperature on bee species richness was mediated by a positive effect of moderate grazing on floral resource richness. The study, therefore, reveals that bee communities of the African savannah zone may benefit from low levels of livestock grazing as this favors the growth of flowering plant species. A high level of livestock grazing intensity will cause significant species losses, an effect that may increase with climatic warming. Chapter III: Agricultural intensification with seasonal fallow land promotes high bee diversity in Afrotropical drylands This study investigated the impact of local agriculture intensification on bee diversity in the Afro tropical drylands of northern Tanzania. Using sweep netting and pan traps, a total of 219 species (from 3,428 individuals) representing 58 genera and six families were collected from 24 study sites (distributed from 702 to 1708 m. asl) representing three levels of agriculture intensity spanning an extensive gradient of mean annual temperature. Results showed that bee species richness increased with agricultural intensity and with increasing temperature. However, the effects of agriculture intensity and temperature on bee species richness were mediated by the positive effects of agriculture and temperature on floral resource richness used by bee pollinators. Moreover, results showed that variation of bee body sizes increases with agricultural intensification, "that effect", however, diminished in environments with higher temperatures. This study reveals that bee assemblages in Afrotropical drylands benefit from agriculture intensification in the way it is currently practiced. Further intensification, including year-round irrigated crop monocultures and extensive use of agrochemicals, is likely to exert a negative impact on bee diversity and pollination services, as reported in temperate regions. Moreover, several bee species were restricted to natural savannah habitats. Therefore, to conserve bee communities in Afro tropical drylands and guarantee pollination services, a mixture of savannah and agriculture, with long periods of fallow land should be maintained. Chapter IV: Impact of land use intensification and local features on plants and pollinators in Sub-Saharan smallholder farms For the first time in the region, this study explores the impact of land-use intensification on plants and pollinators in Sub-Saharan smallholder farms. The study complemented field surveys of bees with a modern DNA metabarcoding approach to characterize the foraged plants and thus built networks describing plant-pollinator interactions at the individual insect level. This information was coupled with quantitative traits of landscape composition and floral availability surrounding each farm. The study found that pollinator richness decreased with increasing impervious and agricultural cover in the landscape, whereas the flower density at each farm correlated with pollinator richness. The intensification of agricultural land use and urbanization correlated with a higher foraging niche overlap among pollinators due to the convergence of individuals' flower-visiting strategies. Furthermore, within farms, the higher availability of floral resources drove lower niche overlap among individuals, greater abundance of flower visitors shaped higher generalization at the networks level (H2I), possibly due to increased competition. These mechanistic understandings leading to individuals' foraging niche overlap and generalism at the network level, could imply stability of interactions and the pollination ecosystem service. The integrative survey proved that plant-pollinator systems are largely affected by land use intensification and by local factors in smallholder farms of Sub-Saharan Africa. Thus, policies promoting nature-based solutions, among which the introduction of more pollinator-friendly practices by smallholder farmers, could be effective in mitigating the intensification of both urban and rural landscapes in this region, as well as in similar Sub-Saharan contexts. Chapter V: A synopsis of the Bee occurrence data of northern Tanzania This study represents a synopsis of the bee occurrence data of northern Tanzania obtained from a survey in the Kilimanjaro, Arusha, and Manyara regions. Bees were sampled using two standardized methods, sweep netting and colored pan traps. The study summed up 953 species occurrences of 45 species belonging to 20 genera and four families (Halictidae, Apidae, Megachilidae, and andrenidae) A. This study serves as the baseline information in understanding the diversity and distribution of bees in the northern parts of the country. Understanding the richness and distribution of bees is a critical step in devising robust conservation and monitoring strategies for their populations since limited taxonomic information of the existing and unidentified bee species makes their conservation haphazard. Chapter VI: General discussion In general, findings obtained in these studies suggest that livestock grazing and agriculture intensification affects bee assemblages and floral resources used by bee pollinators. Results have shown that moderate livestock grazing intensity may be important in preserving bee diversity. However, high level of livestock grazing intensity may result in a strong decline in bee species richness and abundance. Moreover, findings indicate that agriculture intensification with seasonal fallow lands supports high floral resource richness promoting high bee diversity in Afrotropical drylands. Nonetheless, natural savannahs were found to contain unique bee species. Therefore, agriculture intensification with seasonal fallow should go in hand with conserving remnant savannah in the landscapes to increase bee diversity and ensure pollination services. Likewise, findings suggest that increasing urbanization and agriculture cover at the landscape level reduce plant and pollinator biodiversity with negative impacts on their complex interactions with plants. Conversely, local scale availability of floral resources has shown the positive effects in buffering pollinators decline and mitigating all detrimental effects induced by land-use intensification. Moreover, findings suggest that the impact of human land use (livestock grazing and agriculture) do not act in isolation but synergistically interacts with climatic factors such as mean annual temperature, MAT. The impact of MAT on bee species richness in grazing gradient showed to be more detrimental than in agriculture habitats. This could probably be explained by the remaining vegetation cover following anthropogenic disturbance. Meaning that the remaining vegetation cover in the agricultural gradient probably absorbs the solar radiations hence reducing detrimental effect of mean annual temperature on bee species richness. This one is not the case in grazing gradient since the impact of livestock grazing is severe, leaving the bare land with no vegetation cover. Finally, our findings conclude that understanding the interplay of multiple anthropogenic activities and their interaction with MAT as a consequence of ongoing climate change is necessary for mitigating their potential consequences on bee assemblages and the provision of ecosystem services. Morever, future increases in livestock grazing and agriculture intensification (including year-round crop irrigated monocultures and excessive use of agrochemicals) may lead to undesirable consequences such as species loss and impair provision of pollination services.}, subject = {Human land use}, language = {en} } @article{HauptsteinForsterNadernezhadetal.2022, author = {Hauptstein, Julia and Forster, Leonard and Nadernezhad, Ali and Horder, Hannes and Stahlhut, Philipp and Groll, J{\"u}rgen and Blunk, Torsten and Teßmar, J{\"o}rg}, title = {Bioink Platform Utilizing Dual-Stage Crosslinking of Hyaluronic Acid Tailored for Chondrogenic Differentiation of Mesenchymal Stromal Cells}, series = {Macromolecular Bioscience}, volume = {22}, journal = {Macromolecular Bioscience}, number = {2}, doi = {10.1002/mabi.202100331}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257556}, pages = {2100331}, year = {2022}, abstract = {3D bioprinting often involves application of highly concentrated polymeric bioinks to enable fabrication of stable cell-hydrogel constructs, although poor cell survival, compromised stem cell differentiation, and an inhomogeneous distribution of newly produced extracellular matrix (ECM) are frequently observed. Therefore, this study presents a bioink platform using a new versatile dual-stage crosslinking approach based on thiolated hyaluronic acid (HA-SH), which not only provides stand-alone 3D printability but also facilitates effective chondrogenic differentiation of mesenchymal stromal cells. A range of HA-SH with different molecular weights is synthesized and crosslinked with acrylated (PEG-diacryl) and allylated (PEG-diallyl) polyethylene glycol in a two-step reaction scheme. The initial Michael addition is used to achieve ink printability, followed by UV-mediated thiol-ene reaction to stabilize the printed bioink for long-term cell culture. Bioinks with high molecular weight HA-SH (>200 kDa) require comparably low polymer content to facilitate bioprinting. This leads to superior quality of cartilaginous constructs which possess a coherent ECM and a strongly increased stiffness of long-term cultured constructs. The dual-stage system may serve as an example to design platforms using two independent crosslinking reactions at one functional group, which allows adjusting printability as well as material and biological properties of bioinks.}, language = {en} } @phdthesis{Janzen2022, author = {Janzen, Dieter}, title = {Functional analysis of ion channels and neuronal networks in 2D and 3D \(in\) \(vitro\) cell culture models}, doi = {10.25972/OPUS-25170}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-251700}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {In the central nervous system, excitatory and inhibitory signal transduction processes are mediated by presynaptic release of neurotransmitters, which bind to postsynaptic receptors. Glycine receptors (GlyRs) and GABAA receptors (GABAARs) are ligand-gated ion channels that enable synaptic inhibition. One part of the present thesis elucidated the role of the GlyRα1 β8 β9 loop in receptor expression, localization, and function by means of amino acid substitutions at residue Q177. This residue is underlying a startle disease phenotype in the spontaneous mouse model shaky and affected homozygous animals are dying 4-6 weeks after birth. The residue is located in the β8 β9 loop and thus part of the signal transduction unit essential for proper ion channel function. Moreover, residue Q177 is involved in a hydrogen network important for ligand binding. We observed no difference in ion channel trafficking to the cellular membrane for GlyRα1Q177 variants. However, electrophysiological measurements demonstrated reduced glycine, taurine, and β alanine potency in comparison to the wildtype protein. Modeling revealed that some GlyRα1Q177 variants disrupt the hydrogen network around residue Q177. The largest alterations were observed for the Q177R variant, which displayed similar effects as the Q177K mutation present in shaky mice. Exchange with structurally related amino acids to the original glutamine preserved the hydrogen bond network. Our results underlined the importance of the GlyR β8 β9 loop for proper ion channel gating. GlyRs as well as GABAARs can be modulated by numerous allosteric substances. Recently, we focused on monoterpenes from plant extracts and showed positive allosteric modulation of GABAARs. Here, we focused on the effect of 11 sesquiterpenes and sesquiterpenoids (SQTs) on GABAARs. SQTs are compounds naturally occurring in plants. We tested SQTs of the volatile fractions of hop and chamomile, including their secondary metabolites generated during digestion. Using the patch-clamp technique on transfected cells and neurons, we were able to observe significant GABAAR modulation by some of the compounds analyzed. Furthermore, a possible binding mechanism of SQTs to the neurosteroid binding site of the GABAAR was revealed by modeling and docking studies. We successfully demonstrated GABAAR modulation by SQTs and their secondary metabolites. The second part of the thesis investigated three-dimensional (3D) in vitro cell culture models which are becoming more and more important in different part of natural sciences. The third dimension allows developing of complex models closer to the natural environment of cells, but also requires materials with mechanical and biological properties comparable to the native tissue of the encapsulated cells. This is especially challenging for 3D in vitro cultures of primary neurons and astrocytes as the brain is one of the softest tissues found in the body. Ultra-soft matrices that mimic the neuronal in vivo environment are difficult to handle. We have overcome these challenges using fiber scaffolds created by melt electrowriting to reinforce ultra-soft matrigel. Hence, the scaffolds enabled proper handling of the whole composites and thus structural and functional characterizations requiring movement of the composites to different experimental setups. Using these scaffold-matrigel composites, we successfully established methods necessary for the characterization of neuronal network formation. Before starting with neurons, a mouse fibroblast cell line was seeded in scaffold-matrigel composites and transfected with the GlyR. 3D cultured cells displayed high viability, could be immunocytochemically stained, and electrophysiologically analyzed. In a follow-up study, primary mouse cortical neurons in fiber-reinforced matrigel were grown for up to 21 days in vitro. Neurons displayed high viability, and quantification of neurite lengths and synapse density revealed a fully formed neuronal network already after 7 days in 3D culture. Calcium imaging and patch clamp experiments demonstrated spontaneous network activity, functional voltage-gated sodium channels as well as action potential firing. By combining ultra-soft hydrogels with fiber scaffolds, we successfully created a cell culture model suitable for future work in the context of cell-cell interactions between primary cells of the brain and tumor cells, which will help to elucidate the molecular pathology of aggressive brain tumors and possibly other disease mechanisms.}, subject = {Zellkultur}, language = {en} } @phdthesis{Leinweber2022, author = {Leinweber, Jonas}, title = {Untersuchung zur pathophysiologischen Rolle und therapeutischen Relevanz der neuen Inhibitoren der plasmatischen Blutgerinnung Agaphelin und Ixolaris im experimentellen Schlaganfallmodell der Maus}, doi = {10.25972/OPUS-25292}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-252921}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Beim isch{\"a}mischen Schlaganfall f{\"u}hrt ein thrombotischer Verschluss von gehirnversorgenden Arterien zu einer akuten Durchblutungsst{\"o}rung, mit der Folge von neurologischen Defiziten. Prim{\"a}res Therapieziel ist es, diese Blutgerinnsel aufzul{\"o}sen, um die Sauerstoffversorgung des Gehirns wiederherzustellen und den isch{\"a}mischen Hirnschaden zu begrenzen. Dazu stehen die intraven{\"o}sen Thrombolyse mit rt-PA (rekombinanter Gewebe-Plasminogen-Aktivator) sowie die endovaskul{\"a}re mechanische Thrombektomie zur Verf{\"u}gung. H{\"a}ufig kann ein Schlaganfall, trotz erfolgreicher Rekanalisation der Gef{\"a}ße, zu einer weiteren Gr{\"o}ßenzunahme des Infarktes und neurologischen Defiziten bei den Patienten f{\"u}hren. Diese Gr{\"o}ßenzunahme beruht zum einen auf einem sich entwickelnden Hirn{\"o}dem und zum anderen auf entz{\"u}ndlichen Prozessen. Zahlreiche Hinweise deuten darauf hin, dass der Schlaganfall ein Zusammenspiel aus thrombotischen und entz{\"u}ndlichen Ereignissen ist, ein Ph{\"a}nomen, das als Thromboinflammation bezeichnet wird. Aufgrund der begrenzten Behandlungsm{\"o}glichkeiten ist die Entwicklung neuer Therapieans{\"a}tze f{\"u}r den isch{\"a}mischen Schlaganfall besonders wichtig. Agaphelin und Ixolaris sind Proteine aus den Speicheldr{\"u}sen von H{\"a}matophagen, f{\"u}r welche in fr{\"u}heren Studien eine starke antithrombotische Wirkung bei gleichzeitig geringem Blutungsrisiko nachgewiesen wurde. Diese m{\"o}glichen antithrombotischen Effekte wurden in dieser Studie im Hinblick auf ihre Wirksamkeit und Sicherheit im Mausmodell der zerebralen Isch{\"a}mie untersucht. Die Behandlung der M{\"a}use mit Agaphelin 1 Stunde nach transienter Okklusion der Arteria cerebri media (tMCAO) f{\"u}hrte zu kleineren Schlaganfallvolumina und geringeren neurologischen Defiziten an Tag 1 nach dem Schlaganfall. Die Mortalit{\"a}t der M{\"a}use war bis Tag 7 deutlich gesunken. Aus klinischer Sicht ist ebenfalls relevant, dass der starke antithrombotische Effekt von Agaphelin im Mausmodell nicht mit einem erh{\"o}hten Risiko f{\"u}r intrazerebrale Blutungen einherging. Diesem protektiven Effekt von Agaphelin lagen eine verminderte intrazerebrale Thrombusbildung, eine abgeschw{\"a}chte Entz{\"u}ndungsantwort und eine Stabilisierung der Blut-Hirn-Schranke sowie eine Reduzierung der Apoptose zugrunde. Nach der Gabe von Ixolaris 1 Stunde nach tMCAO waren zwar signifikant geringere Infarktgr{\"o}ßen messbar, diese f{\"u}hrten allerdings nicht zu einer Verbesserung der neurologischen Defizite. Zudem verursachte die Gabe von Ixolaris schon 24 Stunden nach tMCAO erhebliche intrazerebrale Blutungen und auch die Mortalit{\"a}t der M{\"a}use war zu diesem Zeitpunkt bereits erh{\"o}ht. Aufgrund dieser massiven Nebenwirkungen scheint Ixolaris kein geeigneter Kandidat f{\"u}r eine humane Anwendung zu sein. Bei Agaphelin hingegen k{\"o}nnte es sich um einen vielversprechenden Kandidaten f{\"u}r die Behandlung des isch{\"a}mischen Schlaganfalls handeln. Vor einer m{\"o}glichen Testung von Agaphelin in klinischen Studien, sind weitere translationale Untersuchungen notwendig, um ein noch pr{\"a}ziseres Verst{\"a}ndnis f{\"u}r die Wirksamkeit und Sicherheit von Agaphelin zu gewinnen. Insgesamt stellt die Hemmung thromboinflammatorischer Prozesse, ohne eine Erh{\"o}hung der Blutungskomplikationen, eine vielversprechende Option zur Behandlung des isch{\"a}mischen Schlaganfalls dar.}, subject = {Schlaganfall}, language = {de} } @phdthesis{Kranz2022, author = {Kranz, Stefanie}, title = {Morbidit{\"a}t von Nebennieren-Inzidentalomen mit (m{\"o}glicher) autonomer Cortisol-Sekretion - Eine retro- und prospektive Studie mit dem Patientenkollektiv des Universit{\"a}tsklinikums W{\"u}rzburg von 1998 bis 2017}, doi = {10.25972/OPUS-25298}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-252987}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Aufgrund des zunehmenden Einsatzes von Schnittbildgebungen werden immer mehr Nebennieren-Raumforderungen zuf{\"a}llig entdeckt. H{\"a}ufig ist bei diesen Zufallsbefunden („Inzidentalome") laborchemisch eine „autonome Cortisol-Sekretion" auff{\"a}llig, ohne dass jedoch klinische Zeichen eines Glukokortikoid-Exzesses sichtbar w{\"a}ren. Ein florides Cushing-Syndrom f{\"u}hrt bekanntermaßen zu einer erh{\"o}hten kardiovaskul{\"a}ren Morbidit{\"a}t und Mortalit{\"a}t. Ziel unserer Untersuchung war es, die Pr{\"a}valenz kardiovaskul{\"a}rer Risikofaktoren und Ereignisse bei Patienten mit einem Nebennieren-Inzidentalom zu ermitteln. Hierbei wurden die Adenome hinsichtlich ihrer sekretorischen Aktivit{\"a}t in drei Subgruppen eingeteilt („nicht-funktionell", „m{\"o}gliche autonome Cortisol-Sekretion" und „autonome Cortisol-Sekretion") und getrennt voneinander betrachtet. Die vorliegende Einzelzenter-Studie umfasst einen Zeitraum von 20 Jahren und beinhaltet sowohl retro- als auch prospektive Elemente. Insgesamt konnten 260 Patienten mit einem Nachsorgeintervall von durchschnittlich fast 9 Jahren inkludiert werden. Die Raten von arterieller Hypertonie, Diabetes mellitus und Dyslipid{\"a}mie stiegen mit zunehmender Cortisol-Sekretion an; dies war sowohl bei der Erstdiagnose als auch bei der letzten erfassten Nachsorge zu beobachten. Patienten mit einem nicht-funktionellen Adenom wiesen nach der Erstdiagnose eine signifikant geringere Inzidenz kardiovaskul{\"a}rer Ereignisse auf als Patienten mit einer autonomen Cortisol-Sekretion. Mittels einer multivariaten Cox-Regression wurden die H{\"o}he des Serumcortisols im Dexamethason-Suppressionstest und eine positive Eigenanamnese als signifikante Einflussfaktoren f{\"u}r das Auftreten kardiovaskul{\"a}rer Ereignisse ermittelt. Eine klinisch unterschwellige, jedoch chronische Cortisol-Exposition im Sinne einer autonomen Cortisol-Sekretion erh{\"o}ht demnach das Risiko der betroffenen Patienten f{\"u}r die Entwicklung von Herz-Kreislauf-Erkrankungen.}, subject = {Nebenniere}, language = {de} } @phdthesis{Lex2022, author = {Lex, Veronika}, title = {Auswirkung verschiedener Ausreifungscocktails auf die Kreuzpr{\"a}sentationsf{\"a}higkeit dendritischer Zellen}, doi = {10.25972/OPUS-25333}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-253334}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Ziel dieser Arbeit war die Entwicklung optimaler DCs f{\"u}r die Generierung von therapeutischen Tumorvakzinen. Neben den essenziellen Eigenschaften der DCs wie der Migrationsf{\"a}higkeit, der Hochregulation kostimulatorischer Molek{\"u}le sowie der Zytokinaussch{\"u}ttung, ist auch die optimale Aufnahme von Tumor-spezifischen Antigenen und deren Pr{\"a}sentation besonders wichtig, um eine effiziente Immunantwort zur erm{\"o}glichen. Wichtigstes Ziel war es {\"u}ber einen optimalen Ausreifungscocktail der DCS eine effektive Antwort der zytotoxischen CD8\(^+\)-Zellen zu erzielen. Dies geschieht im Rahmen der Pr{\"a}sentation von z.B. exogenen Antigenen wie in unserem Falle eines CMV-Proteins {\"u}ber den Weg der sogenannten Kreuzpr{\"a}sentation. Hierzu wurde im Rahmen dieser Arbeit der in unserer Klinik etablierte zytokinbasierte Ausreifungscocktail (IL-1β, TNFα) mit einem Ausreifungscocktail, welcher Toll-like-Rezeptor-Agonisten mit PGE\(_2\) kombiniert, verglichen. Wir konnten erstmals zeigen, dass PGE\(_2\) nicht nur einen Einfluss auf die Ausreifung, Zytokinproduktion und somit Migrationsf{\"a}higkeit der DCs hat wie in der Literatur beschrieben, sondern auch auf die Kreuzpr{\"a}sentationsf{\"a}higkeit exogener Antigene. Das Weglassen von PGE\(_2\) im Cocktail 2 f{\"u}hrte zu einer signifikant besseren Kreuzpr{\"a}sentationsf{\"a}higkeit. Somit l{\"a}sst sich durch unsere Experimente auf eine hemmende Wirkung von PGE\(_2\) auf die T-Zell-Aktivierung {\"u}ber die Kreuzpr{\"a}sentation schließen. Als m{\"o}gliche Schlussfolgerung unserer Experimente sollte bei der Arbeit mit Antigenen, welche {\"u}ber Kreuzpr{\"a}sentation eine T-Zell-Antwort ausl{\"o}sen (Proteine, Tumorlysat, long-peptides) auf die Zugabe von PGE\(_2\) im Ausreifungscocktail verzichtet werden.}, subject = {Dendritische Zelle}, language = {de} } @phdthesis{Vyalkova2022, author = {Vyalkova, Anna}, title = {Efficacy of approved Smallpox Vaccines in Human and Canine Cancer Therapy: Adipose - tissue derived Stem Cells (ADSC) take up VACV and serve as a protective vehicle for virus delivery to tumors}, doi = {10.25972/OPUS-25345}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-253457}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Cancer is one of the major causes of mortality in developed countries. In 2020, there were more than 19.3 million new cases of tumor malignancies worldwide, with more than 10 million deaths. The high rates of cancer cases and mortality necessitate extensive research and the development of novel cancer treatments and antitumor agents. In most cases, conventional treatment strategies for tumor therapy are based on chemotherapeutic treatment, which is supplemented with radiotherapy and/or surgical resection of solid tumors [1]. The use of chemotherapy for the treatment of cancer has significant side effects, the most dangerous of which is toxicity [2] [3]. Modern methods of treating tumors focus on specific drug delivery to the tumor site, actively targeting the tumor cells, as well as the reduction of side effects. One of the most promising current approaches is based on oncolytic viruses. Antitumor properties of viruses were documented at the beginning of the 20th century when some cancer patients recovered after acute viral infections, particularly influenza [4]. Vaccinia virus (VACV) is a member of the Poxviridae family, has natural antitumor properties, and provides a good basis for generating efficient recombinant oncolytic strains. Furthermore, VACV has never been shown to integrate into the host genome [5]. VACV is likely one of the safest and well-studied viruses due to extensive research being done in molecular biology and pathophysiology to investigate its potential as a vaccine for smallpox eradication programs. It has been administered to over 200 million people worldwide. VACV antitumor therapeutic effectiveness has been established in xenograft models with a variety of tumor types for human and canine cancers. Furthermore, recombinant oncolytic VACVs expressing genes encoding light-emitting proteins are a big improvement in a treatment strategy that combines tumor-specific therapies and diagnostics. Oncolytic virus treatments are effective in xenograft cancer models in mice, however, the significant improvements found in mice do not always translate to human cancer patients. These therapies should be tested in dogs with spontaneous cancer not only to offer well translatable information regarding the possible efficiency of viral therapy for human cancers but also to improve the health of our household pets as well. Spontaneous canine tumors are starting to be regarded as an essential model of human cancers that can reproduce the tumor microenvironment and immune response of cancer patients [6]. Just as data obtained in dog experiments can improve cancer therapy for human patients, these findings can also be used to improve treatment protocols in canine patients. Hundreds of studies and dozens of reviews have been published regarding the antitumor effects of various recombinants of VACV, but information on the anticancer features of initial, genetically-unmodified "na{\"i}ve" VACV is still limited. In the first studies, we compared different wild-type, non-modified strains of VACV and tested their oncolytic properties on a panel of various cancer cells derived from different organs. In addition, we also tested a protection system based on the "Trojan horse" concept - using a combination of human Adipose tissue-derived Stem Cells (hADSC) and three different wild-type single plaque purified Vaccinia virus strains: W1, L1, and T1. We showed that all tested human cell lines (FaDu, MDA MB 231, HNT-13, HNT-35, and PC-3) are permissive to L0, W0, T0, L1, W1, and L1 infection. Furthermore, we tested the cytotoxicity of VACV in different cancer cell lines (A549, PC-3, MDA-MB 231, FaDu, HNT-13, HNT-25, and HNT-35). All strains lysed the cells, which was most visible at 96 hpi. We also showed that all tested strains could efficiently infect and multiply in hADSC at a high level. In our in vivo study, we tested the therapeutic efficacy of the wild-type Vaccinia viruses L1, W1, and T1 alone or in combination with hADSC. Wild-type VACV strains were tested for their oncolytic efficiency in human lung adenocarcinoma (A549) in a xenograft model. Treatment of A549 tumors with different doses of L1 and W1 as well as with a L1/ADSC or W1/ADSC combination led to significant tumor regression compared to the PBS control. Additionally, the treatment with L1 and W1 and the combination of L1/ADSC and W1/ADSC was well tolerated by the animals. In the case of the wild-type Tian Tan strain, results were not obtained due to the high cytotoxicity of this strain. Therefore, it should be attenuated for further studies. In the second part of the current study, we investigated the oncolytic effect of C1-opt1, W1 opt1, and L3-opt1 strains based on the wild-type Copenhagen, Wyeth, and Lister vaccines with additional expression of turboFP635. Replication and cytotoxicity assays demonstrated that all 3 viruses were able to infect, replicate in and kill canine tumor cell lines STSA-1 and CT1258 in a virus dose- and time- dependent fashion. Cytotoxicity and replication assays were also performed on cultured canine Adipose-derived Mesenchymal Stem Cells (cAdMSC). The results showed that the cells were lysed much slower than the tumor cells. It suggests that these cells can harbour the virus for a long-term period, allowing the virus to spread into the body and there is enough time to reach the primary tumor or metastases before the cell carrier is destroyed. The viral replication in cAdMSC in our study was lower than in canine cancer cells (STSA-1 and CT1258) at the same MOI. After being studied in cell culture, C1 opt1 and their combination with cAdMSC (C1-opt1/cAdMSC) were used in canine STSA 1 tumor bearing nude mice. We tested the oncolytic effect of the C1-opt1 virus alone and in combination with cAdMSC in the canine STSA-1 xenograft mouse model. Altogether, our findings have shown that both C1-opt1 and cAdMSC/C1-opt1 significantly reduced tumor size or eliminated the tumor. There was no significant difference between C1-opt1 alone and cAdMSC/C1-opt1. The virus particles were mostly found within the tumor after 24 dpi, some amount of virus particles were found in the lungs of mice injected with a combination of cAdMSC/C1-opt1 but not in the group injected with virus alone (cAdMSC might get stuck in the lungs and cause virus propagation there). Taken together, this study provided a proof-of-concept that hADSC/cAdMSC can be used as a carrier system for the "Trojan horse" concept. However, it should be confirmed in another experimental model system, such as canine patients. Moreover, these findings suggest that wild-type, non-modified strains of Vaccinia virus isolates can be considered promising candidates for oncolytic virotherapy, especially in combination with mesenchymal stem cells.}, subject = {ADSC}, language = {en} }