Files and links (1)
Free to read and download, Open Access
Dissertation
Che6 chemosensory regulation of multicellularity in myxococcus xanthus
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2011
DOI: 10.17077/etd.djr5zyui
Abstract
<p><em>Myxococcus xanthus<em> is a δ-proteobacterium that displays a complex, multicellular life cycle involving vegetative growth, coordinated motility, and a developmental program culminating in sporulation. <em>M. xanthus<em> utilizes two genetically distinct yet coordinated systems to regulate motility comprised of either Type IV pili (T4P) or focal adhesion complexes (FAC). Both motility systems are regulated, in part, by multiple chemosensory systems. During development, cells aggregate into foci and gradually lose motility to become quiescent fruiting bodies containing mature heat- and sonication-resistant myxospores. In this study, I have characterized a new chemosensory system, Che6, in <em>M. xanthus<em> for its role in motility and development. The Che6 chemosensory system is comprised by six homologs to known chemotaxis proteins, Mcp6, CheW6a, CheW6b, CheA6, CheR6, and CheB6 and includes two previously identified proteins, a potassium efflux channel (KefC) and a sensor kinase (SocD).</p>
<p>Mutations in each of the corresponding genes were found to affect motility and to disrupt development. Notably, the motility defects were well defined in a background strain with an impaired T4P system. In this background, the che6 mutants were observed to either positively or negatively affect reversal frequencies, highlighting their role in either FAC or T4P-based motility systems. Developmental defects were also identified for the che6 mutants and affected the timing of aggregation and sporulation. Interestingly, the overproduction of the CheB6 methylesterase resulted in spore formation independent of fruiting body formation. Uncoupling of sporulation and fruiting body formation for this mutant was found to be independent of a key developmental signal known as the C-signal.</p>
<p>Moreover, we have demonstrated for the first time the association of a potassium efflux channel (KefC) with a chemosensory system (Che6) in bacteria. In this study, we provide evidence demonstrating that KefC provides an input signal for Mcp6 which transduces a signal through CheA to the histidine kinase SocD which serves as an output to regulate both motility and development in <em>M. xanthus<em>.</p>
Details
- Title: Subtitle
- Che6 chemosensory regulation of multicellularity in myxococcus xanthus
- Creators
- Jodie Catherine Scott - University of Iowa
- Contributors
- John R. Kirby (Advisor)Linda L. McCarter (Committee Member)Alexander R. Horswill (Committee Member)Steven Clegg (Committee Member)Ernesto Fuentes (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Microbiology
- Date degree season
- Spring 2011
- Publisher
- University of Iowa
- DOI
- 10.17077/etd.djr5zyui
- Number of pages
- xii, 161 pages
- Copyright
- Copyright © 2011 Jodie Catherine Scott
- Comment
This thesis has been optimized for improved web viewing. If you require the original version, contact the University Archives at the University of Iowa: https://www.lib.uiowa.edu/sc/contact/.
- Language
- English
- Description bibliographic
- Includes bibliographical references (pages 152-161).
- Academic Unit
- Microbiology and Immunology
- Record Identifier
- 9983776753102771
Metrics
640 File views/ downloads
286 Record Views