Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 05/06

The startle response as a measure in mouse models of mood disorders

Ein großer Teil der Fragestellungen in den Neurowissenschaften beschäftigt sich mit dem Thema, wie das Säugerhirn Verhalten auslöst und steuert. Die Schreckreaktion ist ein relativ einfaches Verhalten, welches bei Säugetieren ohne großen Aufwand ausgelöst werden kann und variabel auf eine Vielfalt von experimentellen Behandlungen reagiert. Das Ziel der vorliegenden Arbeit war es, Schreckreaktions-Messungen am Max-Planck- Institut für Psychiatrie in München (MPI-P) zu etablieren. Vor dem Hintergr...

Interspecies interaction and diversity of green sulfur bacteria

The following work is shedding light on the phylogenetic classification on the family of the Chlorobiacea, the members of which are showing signs of preadaptation to symbiosis. Symbioses consisting of purely prokaryotic associations between phylogenetically distinct bacterial species have been widely documented. Only few are available as a laboratory culture to elucidate the molecular basis of their interaction. One of these few model organisms is the phototrophic consortium “Chlorochromatium ag...

Heterogeneity and timing in the quorum sensing system of Vibrio harveyi

Bacteria produce and excrete signaling molecules, so called autoinducers, which allow them to monitor their population density and/or their environment in a process best known as quorum sensing. The Gram-negative marine bacterium Vibrio harveyi regulates certain virulence factors like type III secretion, siderophore production, and exoproteolytic activity as well as biofilm formation and bioluminescence using quorum sensing. The bacterium produces three different autoinducers: HAI-1, a N-(3-hydr...

Psidin is required for neuron survival and axon targeting through two distinct molecular mechanisms in Drosophila

The formation of neuronal networks depends on the proper development and targeting of the neurons within the network. One key challenge during the development of such networks is the correct cross linking of axons and dendrites. Only correct synapse formation between dendrites and axons will allow neurons to contribute to the entire network. Therefore further insights into axon targeting mechanisms will help to understand the underlying developmental processes and contribute to future cures for ...

Untersuchungen von menschlichen Zellen mit ungewöhnlicher Chromatin-Anordnung und Zellkernform

Extensive changes of higher order chromatin arrangements can be observed during prometaphase, terminal cell differentiation and cellular senescence. Experimental systems where major reorganization of nuclear architecture can be induced under defined conditions, may help to better understand the functional implications of such changes. Here, we report on profound chromatin reorganization in fibroblast nuclei by chaetocin, a thiodioxopiperazine metabolite. Chaetocin induces strong condensation of ...

On the way to differentiation

Functional analysis of DOT1-dependent histone H3 lysine 76 methylation during cell cycle progression in Trypanosoma brucei

The role of Ebf2 in normal and malignant hematopoiesis

Encoding of saccadic scene changes in the mouse retina

The task of the visual system is to extract behaviourally relevant information from the visual scene. A common strategy for most animals ranging from insects to humans is to constantly reposition gaze by making saccades within the scene. This ‘fixate and saccade’ strategy seems to pose a challenge, as it introduces a highly blurred image on the retina during a saccade, but at the same time acquires a ‘snapshot’ of the world during every fixation. The visual signals on the retina are thus segment...

Innovations in rabies virus rescue

Behavioural and hormonal aspects of the breeding ecology in sex-role reversed polyandrous birds

Neural circuit analysis of the dorsal nucleus of the lateral lemniscus and new viral approaches to neural circuit analysis in Mongolian gerbils

Auditory stimuli are processed by several parallel and serial neural circuits in the auditory brainstem. In the first part of this PhD thesis, synaptic integration of excitatory inputs in the neural network of the dorsal nucleus of the lateral lemniscus (DNLL) in Mongolian gerbils is investigated. The second part of this study analyses the feasibility of the use of viral vectors in Mongolian gerbils. This work aims to add to the available methods for neural circuit analysis in these animals by e...

Das Phagenschock-Protein LiaH aus Bacillus subtilis

Für das Überleben von Bacillus subtilis ist eine verlässliche Überwachung der Integrität der Zellhülle essentiell, um diese zu schützen und bei Schäden adäquat zu reagieren. Neben den ECF � Faktoren spielen Zwei-Komponenten-Systeme (2KS) in der Zellhüllstressantwort von B. subtilis eine zentrale Rolle. Eines dieser Systeme, das LiaRS- 2KS reagiert auf eine große Anzahl verschiedener Zellwand-Antibiotika sowie andere zellhüllstress-auslösende Substanzen. Die zelluläre Funktion und Rolle des Lia-S...

The role of DNA modifications in pluripotency and differentiation

DNA methylation plays a crucial role in the epigenetic control of gene expression during mammalian development and differentiation. Whereas the de novo DNA methyltransferases (Dnmts), Dnmt3a and Dnmt3b, establish DNA methylation patterns during development; Dnmt1 stably maintains DNA methylation patterns during replication. DNA methylation patterns change dynamically during development and lineage specification, yet very little is known about how DNA methylation affects gene expression profiles ...

Identi cation of novel molecular factors involved in individual stress vulnerability

Stress is part of everyday life. And while acute and short periods of stress can help to overcome challenges, exposure to chronic - and especially uncontrollable - stress can lead to maladaption of the organism, which can ultimately increase the risk of disease. However, vulnerability to stress and vulnerability to risk increases are strongly dependent on the individual. The molecular underpinnings of this vulnerability and resilience are still largely unknown. Therefore, the present thesis aims...

Systematics and evolution of the Acochlidia (Gastropoda, Euthyneura) - a microanatomical approach by means of 3D reconstruction using Amira

Only a small fraction of the estimated species diversity on Earth already has been discovered, and expected high extinction rates force biologists to rapid surveys. Molecular barcoding techniques meet such goals, but taken alone they can hardly connect genetic discoveries with the large morphology-based body of taxonomic knowledge that accumulated during centuries. Also, the study of organismic evolution requires reliable information on phenotypes. Morphological and biological knowledge on forma...

Phylogenetic and functional analyses of stress-responsive bacterial transmembrane signal transducing systems

Biogenese des Rieske-Eisen-Schwefel-Proteins der Mitochondrien

Zac1 kontrolliert die astrogliale Differenzierung durch Socs3

CTCF, Lamin A/C und eine Histondeacetylase sind essentiell für die Positionierung des humanen CFTR-Gens an der Zellkernperipherie

Central and peripheral aspects of hypothalamic-pituitary-adrenal (HPA) axis dysfunction

An aberrant regulation of the hypothalamic-pituitary-adrenal (HPA) axis is closely associated with the pathophysiology of affective disorders such as major depression (MD). Accordingly, patients suffering from MD frequently show profound neuroendocrine alterations with hyper- or hypo-cortisolism as a result of a dysregulated stress hormone system. Focussing on this key endophenotype of MD, the ‘stress reactivity’ (SR) mouse model was recently established, consisting of three independent mouse li...

Brain circuit dynamics related to extremes in trait anxiety in mice

Anxiety disorders are among the most common psychiatric diseases and contribute to the development of other psychiatric conditions, such as major depression, leading to a high impairment of daily life quality. Although it is obvious that the physiological architecture of neuronal networks and its modifications are essential for the ability of the brain to process incoming information and to control highly organized behaviour, the mechanisms underlying anxiety disorders still remain poorly unders...

Studies on the release of neutrophil extracellular traps and IFN-γ as part of the innate immune response to Aspergillus fumigatus and on the fungal stress response via the hybrid sensor kinase TcsC

Aspergillus fumigatus is a saprophytic mold that naturally inhabits the soil. Asexual reproduction yields hardy conidia that circulate in the air and are inhaled daily by humans. The fungus seems not to have evolved distinct mechanisms of pathogenicity, but is capable of responding to many stressful environmental cues present in its naturally harsh niche. The robust conidia present no problem to a fully functioning immune system, but if the innate immune system is compromised, the conidia can be...

Characterization of the membrane protein Prat1 in the inner envelope of chloroplasts

Anpassung von Pseudomonas aeruginosa an die Mukoviszidose-Lunge

Rapid neuronal signaling cascades initiated by corticosterone

Besides inducing transcription by activating nuclear receptors, corticosterone (CORT) acts rapidly to alter cellular activity through multiple signaling cascades. Pharmacology-based experiments presented here show that nanomolar doses of CORT activate several pathways in primary hippocampal cultures within 20 minutes, a time-frame that excludes genomic mechanisms mediated by classical glucocorticoid (GR) and mineralocorticoid (MR) nuclear receptors. Moreover, none of these effects were subject t...

Tcf4 is a target gene of the imprinted gene Zac1 during mouse neurogenesis

Identification of MLL-A9 related target genes and microRNAs involved in leukemogenesis

The Arabidopsis MTERF protein PAM48 is required for plastid gene expression and development

The source of innervation and function of palisade endings in the extraocular muscles of Macaca mulatta

Vertebrate extraocular muscles show a highly complex anatomy, which differs in many respects from skeletal muscles. Furthermore, there is a considerable variation among different species with regard to the presence of proprioceptive organs. Whereas muscle spindles and Golgi tendon organs are well developed in sheep and pig, neither are found in cat, and only poorly developed muscle spindles are present in human and monkey. In all vertebrates studied so far cuffs of nerve terminals around multipl...