Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 03/06

Analyse des PeBoW-Komplexes in der Ribosomenbiogenese

Während der Zellproliferation müssen Zellwachstum und Zellteilung koordiniert werden. Die Kopplung erfolgt in der Hefe durch einen Komplex aus Nop7p, Erb1p und Ytm1p, der sowohl an der Ribosomenbiogenese als auch an der Kontrolle der DNA-Replikation beteiligt ist. Die homologen Proteine Pes1, Bop1 und WDR12 werden in Säugern von Zielgenen des Transkriptionsfaktors c-Myc, einem zellulären Onkoprotein, kodiert. In dieser Arbeit wurde die Existenz eines evolutionär konservierten Komplexes aus P...

Dreidimensionale Analysen der Chromatinanordnung in normalen und neoplastischen humanen Kolonepithelzellen anhand von Paraffinschnitten

Regulation des Säure-induzierten Cad-Systems von Escherichia coli durch den membranintegrierten Transkriptionsaktivator CadC und die Lysin-spezifische Permease LysP

Das Cad-System von E. coli gehört zu den Säure-induzierbaren Aminosäure-Decarboxylase-Systemen und spielt eine wichtige Rolle bei der Säureschutzantwort. In diesem System erfolgt die Reizwahr-nehmung, Signaltranslokation über die Membran und Transkriptionsregulation durch ein einziges Protein, nämlich CadC. In Gegenwart von induzierenden Bedingungen (niedriger pH-Wert und Lysin) aktiviert CadC die Expression des cadBA-Operons, dadurch kommt es zur Decarboxylierung von Lysin zu Cadaverin und C...

The function of Mim1 in the biogenesis of the mitochondrial TOM complex

The translocase of the outer mitochondrial membrane (TOM complex) is the general entry site for newly synthesized proteins into the organelle. The translocase is a multi-subunit complex composed of seven subunits: two receptor proteins, Tom70 and Tom20, and five components which form the core complex, Tom40, Tom22, Tom7, Tom6, and Tom5. In this thesis it is shown that Mim1 is required for the integration of the import receptor Tom20 into the outer membrane but not for its assembly into the TO...

Assessment of soil bacterial communities with emphasis on the phylum Acidobacteria

The seasonal culturability (February, April, August) of bacterial cells from a microbial community of an alpine calcareous soil was assessed employing the MicroDrop technique using different laboratory media with humic acid analogs (HA), a mixture of polymers (POL), artificial root exudates (RO), nutrient broth, or soil extract as carbon and energy sources. Thereby, the summer August sample showed the highest culturability value in media supplemented with soil extract (13.5%). Since only 81 w...

The ectomycorrhizal community structure in beech coppices of different age

Abstract – The ectomycorrhizal community structure in Beech coppices of different age The species composition of ectomycorrhizal (ECM) fungal communities can be strongly influenced by the sylvicultural practises, abiotic and biotic factors, which determine interactions among the species. In order to determine the influence of the coppicing on EM community, shoot age, bedrock types, exposure, slope, humus features, soil conditions, sampling points locations were taken into account as the mo...

Plk4-induced Centriole Biogenesis in Human Cells

Die RR-Maus

Funktion und Regulation des melanomassoziierten transkriptionellen Repressors Nab2

Entwicklung neuer Methoden zur massenspektrometrischen Charakterisierung von Membranproteinen

Etwa 30% aller Gene codieren für Membranproteine (MP). Trotz ihrer hohen Relevanz, speziell im medizinischen Bereich, stellt die Analyse von MP aufgrund ihrer physikalisch-chemischen Eigenschaften ein häufiges Problem in der Proteinbiochemie dar. Diese Arbeit soll eine Einsicht in die Problematik geben sowie Lösungsansätze aufzeigen, um den Umgang mit diesen Polypeptiden zu vereinfachen. Ein geeignetes Modellsystem zum Studium der Eigenschaften membranintegraler Proteine und Peptide sowie zur...

Dynamic Echo Analysis In Echo Imaging

The molecular motor kinesin

Tumormilieu-induzierte Inaktivierung zytotoxischer Lymphozyten

The neural mechanisms of persistent inhibition in the DNLL of the gerbil (Meriones unguiculatus)

Analysis of c-MYC-induced chromosomal instability and generation of a conditional microRNA expression system

Development of new methods to study DNA methyltransferase function and protein interactions in living cells

Determinants of the Bacterial Diversity in Manipulated and Natural Soils

Soils harbor highly diverse bacterial communities. It is still poorly understood whether functional redundancy or a multitude of ecological niche modify the abundance and community composition of bacteria in soil. Understanding why soil microorganisms are so diverse and which factors control their community composition is of importance because they are essential for maintaining ecosystem processes and functions. Alterations of biotic or abiotic factors as results of natural or anthropogenic d...

Das zelluläre Immunsystem als Ziel des Influenzavirus Typ A

Das Disulfidbrücken-Transfer-System der Mitochondrien

Nahezu alle mitochondrialen Proteine sind im Zellkern kodiert und werden im Zytosol synthetisiert. Die Komplexe, die den Import von Außenmembran-, Innenmembran- und Matrixproteinen katalysieren, sind relativ gut untersucht. Der Import von Proteinen des mitochondrialen Intermembranraums ist dagegen weniger gut verstanden. Im Rahmen dieser Arbeit wurde der Importmechanismus für lösliche Intermembranraumproteine untersucht, die durch konservierte Cysteinmotive charakterisiert sind. Nach Mia40 ko...

Information Processing at the Calyx of Held Synapse Under Natural Conditions

This study investigates the role of the medial nucleus of the trapezoid body (MNTB) in sound processing. The experimental part focuses on in vitro experiments in acute brain slices of Mongolian gerbils, in parallel a theoretical approach explains the experimental results in the context of a mathematical vesicle-release model. One of the hallmarks of auditory neurons in vivo is spontaneous activity that occurs even in the absence of any sensory stimuli. Sound evoked bursts of discharges are th...

Homöostatische Proliferation und antigenabhängige Aktivierung zytotoxischer T-Zellen in vivo

Dendritische Zellen (DC) übernehmen essentielle Aufgaben in der Homöostase des Immunsys-tems und in der Induktion von Toleranz oder Immunität. Eine besondere Wechselwirkung findet hierbei zwischen DC und T-Zellen statt, welche durch die Präsentation und Erkennung von Selbstpeptiden, beziehungsweise Fremdantigenen, vermittelt wird. DC spielen eine wichtige Rolle bei der Selektion eines funktionellen T-Zell-Kompartiments im Thymus. In der vorliegenden Stu-die wurde die Funktion der Antigenpräse...

A Revision of the European Representatives of the Microlepidopteran Genus Dioryctra Zeller, 1846 (Insecta: Lepidoptera: Pyralidae: Phycitinae)

Improved Genetically-Encoded Calcium Indicators Based on Troponin C

Miscellaneous Contribution to the Anatomy and Molecular phylogeny of tropical African resupinate Thelephorales (Basidiomycota, Fungi)

The Thelephorales (Basidiomycota, Fungi) form a monophyletic group with approximately 177 accepted species. The Thelephorales are cosmopolitan and encompass mainly ectomycorrhizal species. Unlike many fungal lineages, evolutionary trends within and between members of Thelephorales still remain incompletely assessed. Additionally, most phylogenetic investigations on fungi have failed to include representative samples from tropical Africa. In the present study started four years ago, we have as...

In vivo imaging of the degenerating and regenerating nervous system

Regulation of Membrane Traffic at the Golgi Apparatus by Rab GTPases and their GAPs

Consequences of chronic social stress in mice

Alternative reproductive tactics in the ant genus Hypoponera

Chlorochromatium aggregatum

The epibiont of the phototrophic consortium “Chlorochromatium aggregatum” was isolated in pure culture. This was the first time that a symbiotic green sulfur bacterium was isolated in pure culture indicating, that the symbiosis is not an obligate one with respect to the green sulfur bacterium. The phylogenetic affiliation revealed that the epibiont belongs to the genus Chlorobium, accordingly the isolate was named Chlorobium chlorochromatii strain CaD. The cells were gram-negative, nonmo...

Biogenesis of proteins of the mitochondrial intermembrane space

All intermembrane space (IMS) proteins are synthesized in the cytosol and have to be imported into mitochondria. Many proteins of the IMS lack typical N-terminal targeting signals and are characterized by a small molecular mass and highly conserved cysteine residues present in characteristic patterns. These proteins cross the outer membrane of mitochondria via the TOM complex and need their cysteine residues for the efficient retention in the IMS. The aim of this study was to analyse whether ...

Farbverarbeitungsmechanismen in der Humanretina untersucht mit Hilfe der Fourierinterferometrischen Stimulation - FIS

Die vorliegende Arbeit befasst sich mit der Untersuchung der Farbwahrnehmung durch die menschliche Retina. Dabei wird die durch Gemperlein entwickelte Fourier Interferometrischen Stimulation (FIS) eingesetzt, bei der die in einer Lichtquelle enthaltenen spektralen Anteile durch ein linear angesteuertes Michelson-Interferometer mit einer jeweils spezifischen Frequenz moduliert werden. Mit Hilfe der Fouriertransformation kann aus der Ableitung eines solchen Reizes eine Amplituden- und eine Phas...

Genetic Tools for the Analysis of Neural Networks in Flies

Motion vision is of fundamental importance for moving animals from arthropods to mammals. In this thesis I lay ground for the functional analysis of the neural circuit underlying visual motion detection in fruit flies by means of genetic tools. In Drosophila melanogaster transgenic tools allow for both experimental observation and manipulation of neural activity: genetically encoded calcium indicators (GECIs) can be used for the optophysiological characterization of neural activity and transg...

Analysis of p53 and c-MYC, two key transcription factors involved in tumorigenesis

Functional characterization of the mitotic-spindle and kinetochore associated protein astrin

Analysis of the nuclear egress complex of mouse cytomegalovirus

Herpesvirus infections are usually asymptomatic or associated with mild symptoms. Fatal diseases are seen in immune suppressed and immune incompetent individuals. Although herpesviruses are of emerging medical importance nowadays an infection only can be controlled by chemotherapeutics, which target viral DNA replication and cause negative side effects. Essential steps of herpesvirus morphogenesis might indicate new targets for interference. The export of the 110 nm large herpesvirus nucleoca...

Analysis of the DNA damage response in living cells

DNA lesions arising from environmental and endogenous sources induce various cellular responses including cell cycle arrest, DNA repair and apoptosis. Although detailed insights into the biochemical mechanisms and composition of DNA repair pathways have been obtained from in vitro experiments, a better understanding of the interplay and regulation of these pathways requires DNA repair studies in living cells. In this study we employed laser microirradiation and photobleaching techniques in co...

Rolle des Chromatin-Proteins HMGA1a für die Definition von Replikationsursprüngen

Characterization of the Novel Photosynthetic Protein PPP7 involved in Cyclic Electron Flow around PSI

Photosynthetic organisms are able to convert light energy into chemical energy by the operation of the two photosystems, the cytochrome b6/f complex and the ATPase. The two photosystems operate in series during linear electron flow to split H2O and to generate NADP+. During electron transport, a pH gradient is generated across the thylakoid membrane which is used for the generation of ATP. In addition to the linear electron transport mode, ATP can also be produced via cyclic electron flow aro...

The role of the PeBoW-complex in ribosome biogenesis and proliferation of mouse embryonic stem cells

The hallmark of embryonic stem (ES) cells is their ability for self-renewal (capability of unlimited cell division without the loss of pluripotency) as well as for differentiation into all cell types of the adult organism. One factor supposed to be involved in self-renewal is the rapid proliferation rate of ES cells, which is coupled to an unusual cell cycle distribution with the majority of cells in S-phase and a very short G1-phase. This is linked to the lack of a functional G1/S-phase chec...

Identification and initial characterization of the gene sticks and stones as a new regulator of dendrite morphogenesis in Drosophila

Induktion und Selektion allorestringierter, Peptid-spezifischer T-Zellen für die adoptive Therapie von Tumoren

Cooperation between GDNF/Ret and EphrinA/EphA4 signals for motor axon pathway selection in the limb

Revealing the plasticity of polarization in mature hippocampal neurons

Novel approaches for the investigation of sound localization in mammals

The ability to localize sounds in space is important to mammals in terms of awareness of the environment and social contact with each other. In many mammals, and particularly in humans, localization of sound sources in the horizontal plane is achieved by an extraordinary sensitivity to interaural time differences (ITDs). Auditory signals from sound sources, which are not centrally located in front of the listener travel different distances to the ears and thereby generate ITDs. These ITDs are...

Die Rolle humaner NK-Zellen für die Eradikation von Leukämien in der HLA-haploidentischen Knochenmark- und Stammzelltransplantation

Analysis of genomic alterations in malignant melanoma

Granzyme H: A novel cell-death-inducing serine protease

Dissecting the molecular mechanism of glutathione-dependent regulation of cell proliferation and cell death

Dynamic Regulation of Function of the Mitochondrial TIM23 Preprotein Translocase

The vast majority of mitochondrial proteins are synthesized on cytosolic ribosomes in the form of precursor proteins and subsequently imported into mitochondria through the concerted action of the translocases present in the outer and the inner membrane. The TIM23 complex (translocase of the inner membrane) mediates translocation of precursor proteins across or their insertion into the mitochondrial inner membrane in a membrane potential and ATP-dependent manner. The TIM23 complex consists of...

Analysis of the role of Rad5 for the regulation of repair of DSB, small deletions and oxidative damage

Rad5 is a decisive protein in S. cerevisiae due to its role in the Post-replication repair (PRR) pathway, in which Rad5 is necessary for at least one error-free and one error-prone repair subpathway. In addition, Rad5 plays a role in other repair pathways; for instance, Rad5 regulates the balance between the double strand break (DSB) repair pathways, favoring the Rad52-dependent Homologous Recombination (HR) over the yKu70-dependent Non-Homologous-End Joining (NHEJ). Furthermore, since UV-ind...