@phdthesis{Khayenko2023, author = {Khayenko, Vladimir}, title = {Functional peptide-based probes for the visualization of inhibitory synapses}, doi = {10.25972/OPUS-32043}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-320438}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Short functional peptidic probes can maximize the potential of high-end microscopy techniques and multiplex imaging assays and provide new insights into normal and aberrant molecular, cellular and tissue function. Particularly, the visualization of inhibitory synapses requires protocol tailoring for different sample types and imaging techniques and relies either on genetic manipulation or on antibodies that underperform in tissue immunofluorescence. Starting from an endogenous activity-related ligand of gephyrin, a universal marker of the inhibitory post-synapse, I developed a short peptidic multivalent binder with exceptional affinity and selectivity to gephyrin. By tailoring fluorophores to the binder, I have obtained Sylite, a probe for the visualization of inhibitory synapses, with an outstanding signal-to-background ratio, that bests the "gold standard" gephyrin antibodies both in selectivity and in tissue immunofluorescence. In tissue Sylite benefits from simplified handling, provides robust synaptic labeling in record-short time and, unlike antibodies, is not affected by staining artefacts. In super-resolution microscopy Sylite precisely localizes the post-synapse and enables accurate pre- to post-synapse measurements. Combined with complimentary tracing techniques Sylite reveals inhibitory connectivity and profiles inhibitory inputs and synapse sizes of excitatory and inhibitory neurons in the periaqueductal gray brain region. Lastly, upon probe optimization for live cell application and with the help of novel thiol-reactive cell penetrating peptide I have visualized inhibitory synapses in living neurons. Taken together, my work provided a versatile probe for conventional and super-resolution microscopy and a workflow for the development and application of similar compact functional synthetic probes.}, subject = {Fluoreszenzsonde}, language = {en} } @phdthesis{BlancoRedondo2014, author = {Blanco Redondo, Beatriz}, title = {Studies of synapsin phosphorylation and characterization of monoclonal antibodies from the W{\"u}rzburg Hybridoma Library in Drosophila melanogaster}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-93766}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2014}, abstract = {Synapsins are conserved synapse-associated hosphoproteins involved in the fine regulation of neurotransmitter release. The aim of the present project is to study the phosphorylation of synapsins and the distribution of phospho-synapsin in the brain of Drosophila melanogaster. Three antibodies served as important tools in this work, a monoclonal antibody (3C11/α-Syn) that recognizes all known synapsin isoforms and two antisera against phosphorylated synapsin peptides (antiserum PSyn(S6) against phospho-serine 6 and antiserum PSyn(S464) against phospho-serine 464). These antisera were recently generated in collaboration with Bertram Gerber and Eurogentec. ...}, subject = {Synapsine}, language = {en} } @phdthesis{Tupak2013, author = {Tupak, Sara}, title = {Modulators of Prefrontal Fear Network Function: An Integrative View}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85673}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {Regulating our immediate feelings, needs, and urges is a task that we are faced with every day in our lives. The effective regulation of our emotions enables us to adapt to society, to deal with our environment, and to achieve long-term goals. Deficient emotion regulation, in contrast, is a common characteristic of many psychiatric and neurological conditions. Particularly anxiety disorders and subclinical states of increased anxiety are characterized by a range of behavioral, autonomic, and neural alterations impeding the efficient down-regulation of acute fear. Established fear network models propose a downstream prefrontal-amygdala circuit for the control of fear reactions but recent research has shown that there are a range of factors acting on this network. The specific prefrontal cortical networks involved in effective regulation and potential mediators and modulators are still a subject of ongoing research in both the animal and human model. The present research focused on the particular role of different prefrontal cortical regions during the processing of fear-relevant stimuli in healthy subjects. It is based on four studies, three of them investigating a different potential modulator of prefrontal top-down function and one directly challenging prefrontal regulatory processes. Summarizing the results of all four studies, it was shown that prefrontal functioning is linked to individual differences in state anxiety, autonomic flexibility, and genetic predisposition. The T risk allele of the neuropeptide S receptor gene, a recently suggested candidate gene for pathologically elevated anxiety, for instance, was associated with decreased prefrontal cortex activation to particularly fear-relevant stimuli. Furthermore, the way of processing has been found to crucially determine if regulatory processes are engaged at all and it was shown that anxious individuals display generally reduced prefrontal activation but may engage in regulatory processes earlier than non-anxious subjects. However, active manipulation of prefrontal functioning in healthy subjects did not lead to the typical behavioral and neural patterns observed in anxiety disorder patients suggesting that other subcortical or prefrontal structures can compensate for an activation loss in one specific region. Taken together, the current studies support prevailing theories of the central role of the prefrontal cortex for regulatory processes in response to fear-eliciting stimuli but point out that there are a range of both individual differences and peculiarities in experimental design that impact on or may even mask potential effects in neuroimaging research on fear regulation.}, subject = {Neurogenetik}, language = {en} }