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The Global ETD Search service is a free service for researchers
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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The influence of autophagy on the fruiting-body development of the filamentous fungus <i>Sordaria macrospora</i>Voigt, Oliver 17 October 2012 (has links)
Autophagie ist ein Degradationsprozess der streng reguliert ist und in welchem eine eukaryotische Zelle
zelleigene Organellen und Proteine bei Nährstoffmangel abbaut. Außerdem konnte gezeigt werden, dass
dieser Prozess auch in verschiedene Entwicklungsprozesse involviert ist. Die molekulare Entschlüsselung
der Autophagie wurde hauptsächlich in der Bäckerhefe S. cerevisiae vorgenommen. Allerdings ist
Beteiligung der Autophagie an Entwicklungsprozessen in multizellulären filamentösen Ascomyceten
weitestgehend unbekannt. Die Fruchtkörperentwicklung von Pilzen ist ein komplex gestalteter
Differenzierungsprozess der von einem zwei-dimensionalem Pilzgeflecht ausgeht das sich zu einem dreidimensionalem
Perithezium entwickelt. Die Fruchtkörperentwicklung erfordert spezifische
Umgebungsbedingungen und wird durch viele entwicklungsassoziierten Genen reguliert. In dieser Studie
diente der Modellorganismus Sordaria macrospora zur Untersuchung des Einflusses der Autophagie auf
die Fruchtkörperentwicklung. Der coprophytische filamentöse Ascomycet S. macrospora pflanzt sich
lediglich sexuell fort, was ihn ideal für die Fragestellung dieser Arbeit macht. Für diese Arbeit wurden eine
Reihe konservierter Autophagie bezogener Gene auserwählt. Folgende Gene die homolog zu denen anderer
Ascomyceten sind wurden isoliert: Smvps34, Smvps15, Smatg8, Smatg4, und Smjlb1. Durch die Deletion
dieser Gene sollte geklärt werden wie Autophagie in die Fruchtkörperentwicklung involviert ist. Die
Deletion des Phospolipidkinase Gens Smvps34 und des Proteinkinase Gens Smvps15 führte zur Lethalität
von S. macrospora was durch eine Auskeimungsuntersuchung belegt wurde. Die Deletion des Gens
Smatg8, welches eine autophagosomale Strukturkomponente kodiert und des Gens Smatg4, das eine
Cystein-Protease kodiert, die SmATG8 prozessiert, beeinträchtigte ebenfalls die Fruchtkörperentwicklung
und das vegetative Wachstum. Durch Fluoreszenzmikroskopie konnte gezeigt werden, daß SmATG8 in
Autophagosomen lokalisiert und SmATG4 vorwiegend im Zytoplasma lokalisiert ist. Die Prozessierung
von SmATG8 durch SmATG4 wurde ebenfalls durch Fluoreszenzmikroskopie und Western-blot Analyse
bestätigt. Die heterologe Expression von Smatg8 und Smatg4 in S. cerevisiae und der Ape1
Reifungsuntersuchung zeigte, das die cDNA von Smatg8 und Smatg4 den Deletionsphenotyp der jeweiligen
Hefedeletionsmutanten aufheben konnte. Somit konnte die Konservierung dieser beiden Gene innerhalb der
Ascomyceten gezeigt werden. Die Blockade der Fruchtköperentwicklung wurde durch die Deletion des
bZIP Transkriptionsfaktor Gens Smjlb1 verursacht genauso wie die Beeinträchtigung des vegetativen
Wachstums. SmJLB1 ist im Kern lokalisiert und durch qRT-PCR Experimente wurde gezeigt, dass die
Autophagiegene Smatg8 und Smatg4 durch Smjlb1 reguliert werden. Dies läßt vermuten, dass Smjlb1 in den
Prozess der Autophagie involviert ist. Die Ergebnisse dieser Arbeit weisen darauf hin, dass Autophagie und
Fruchtkörperentwicklung des filamentösen Pilzes S. macrospora streng miteinander verknüpft sind.
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Functional analysis of STRIPAK complex components in the filamentous ascomycete Sordaria macrosporaReschka, Eva, Johanna 18 October 2017 (has links)
No description available.
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Investigating the Roles of the Stk Locus in Development, Motility and Exopolysaccharide Production in Myxococcus XanthusLauer, Pamela L. M. 27 June 2007 (has links)
Myxococcus xanthus, a Gram-negative bacterium with a developmental cycle, displays a type IV pili (TFP) mediated surface motility known as social (S) gliding. Beside the polarly localized TFP, the fibril or extracellular polysaccharide (EPS) is also required for S-motility to function. It is proposed that S-motility, along with the related bacterial twitching motility in other species, is powered by TFP retraction. EPS is proposed to anchor and trigger such retractions in M. xanthus. EPS production is known to be regulated by TFP and the Dif signal transduction pathway. Two genetic screens were performed previously to identify additional genes important for EPS production. The first was for the isolation of pilA suppressors, the second for the identification of mutants underproducing EPS in a difA suppressor background. Both screens identified transposon insertions at the stk locus. In particular, StkA, a DnaK homolog, was identified as a possible negative regulator of EPS production by a stkA transposon insertion that suppressed a pilA mutation. A stkB transposon insertion was found to have diminished EPS production in a difA suppressor background.
In this study, in-frame deletion mutants of the five genes at the stk locus, stkY, stkZ, stkA, stkB and stkC, were constructed and examined. In addition, mutations of rbp and bskL, two genes downstream of the stk locus, were constructed. Like transposon insertions, the stkA in-frame deletion resulted in overproduction of EPS. The stkB and to a less extent the stkC mutants underproduced EPS. Mutations in the other genes had no obvious effects on EPS production. Genetic epistasis suggests that StkA functions downstream of TFP and upstream of the Dif sensory proteins in EPS regulation in M. xanthus. Epistasis analysis involving stkB was inconclusive. It is unresolved whether StkB plays a role in the biosynthesis or the regulation of EPS production in M. xanthus. / Master of Science
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Regulation of Exopolysaccharide Production in Myxococcus XanthusBlack, Wesley P. 06 January 2006 (has links)
The surface gliding motility of Myxococcus xanthus is required for a multicellular developmental process initiated by unfavorable growth conditions. One form of the M. xanthus surface motility, social (S) gliding, is mediated by the extension and retraction of polarly localized type IV pili (Tfp). Besides Tfp, exopolysaccharides (EPS), another cell surface associated component, are also required for M. xanthus S motility. Previous studies demonstrated that the Dif chemotaxis-like signal transduction pathway is central to the regulation of EPS production in M. xanthus. Specifically, difA, difC and difE mutants were found to be defective in EPS production and S motility. DifA, DifC and DifE, homologous to methyl-accepting chemotaxis proteins (MCPs), CheW and CheA, respectively, are therefore positive regulators of EPS. This study, undertaken to better understand the regulation of EPS production, led to a few major findings. First, DifD and DifG, homologous to CheY and CheC, respectively, were found to be negative regulators of EPS production. Both DifD and DifG likely function upstream of the DifE kinase in EPS regulation. DifB, which has no homology to known chemotaxis proteins, was found not to be involved in EPS production. Secondly, this study led to the recognition that Tfp likely function upstream of the Dif pathway in the regulation of EPS production. Extracellular complementation experiments suggest that Tfp may act as sensors instead of signals for the Dif chemotaxis-like pathway. We propose a regulatory feedback loop that couples EPS production with Tfp function through the Dif signaling proteins. Lastly, we sought to identify additional genes involved in EPS production. Our efforts identified a mutation in a separate chemotaxis gene cluster as a suppressor of difA mutations, suggesting potential cross-talks among the multiple chemotaxis-like pathways in M. xanthus. In addition, we identified twenty-five previously uncharacterized genes that are predicted to be involved in M. xanthus EPS production. These genes appear to encode additional EPS regulators and proteins with biosynthetic function. / Ph. D.
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Functional and structural analysis of carbonic anhydrases from the filamentous ascomycete Sordaria macrospora / Functional and structural analysis of carbonic anhydrases from the filamentous ascomycete Sordaria macrosporaLehneck, Ronny 09 April 2014 (has links)
No description available.
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Extracellular matrix proteins in growth and fruiting body development of straw and wood degrading basidiomycetes / Extrazelluläre Matrix Proteine bei Wachstum und Fruchtkörperbildung in stroh- und holzabbauenden BasidiomyzetenVelagapudi, Rajesh 24 February 2006 (has links)
No description available.
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Light effects on fruiting body development of wildtype in comparison to light-insensitive mutant strains of the basidiomycete Coprinopsis cinerea, grazing of mites (Tyrophagus putrescentiae) on the strains and production of volatile organic compounds during fruiting body developmentChaisaena, Wassana 17 July 2008 (has links)
No description available.
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モミ根系における外生菌根菌の群集生態学的研究松田, 陽介, MATSUDA, Yosuke 12 1900 (has links) (PDF)
農林水産研究情報センターで作成したPDFファイルを使用している。
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Untersuchung der Fruchtkörperentwicklung bei dem Hyphenpilz Sordaria macrospora / Analysis of fruiting-body development of the filamentous fungus Sordaria macrosporaBernhards, Yasmine 28 October 2010 (has links)
No description available.
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Growth, fruiting body development and laccase production of selected coprini / Navarro González, MónicaNavarro González, Mónica 30 April 2008 (has links)
No description available.
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