Dissertation
Stress survival in Mycobacterium tuberculosis and Mycobacterium bovis and the role of hup in Mycobacterium smegmatis
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2008
DOI:
https://doi.org/10.7273/000005943
Abstract
This study characterizes differences in the abilities of two closely related Mycobacterium species to survive stress. M. tuberculosis and M. bovis are both human pathogens, but M. bovis is also a major animal pathogen and is more virulent in small animal hosts. In this study it was shown that M. bovis was more resistant to the stress of desiccation, low pH, and high heat. Using TLC, this study also demonstrated differences between the cell envelopes of these two species. Finally a comparison of the proteomes made between M. tuberculosis and M. bovis revealed differences in protein expression levels. One protein of interest that had elevated levels in M. bovis was the histone-like protein HupB. In an effort to elucidate the function of HupB in Mycobacterium, the hupB homolog (hup) was deleted from the chromosome of the non-pathogen M. smegmatis. M. smegmatis was chosen for study due to its shorter doubling time and frequent use as a model system for studying its pathogenic counterparts. Initial observation of M. smegmatis Δhup revealed a colony morphology that was smoother than the typical rough colony of wild-type M. smegmatis. Unlike wild-type M. smegmatis, the Δhup strain grew dispersed in liquid cultures, with minimal clumping. Loss of hup does not affect longterm
viability of M. smegmatis but it does leave cells more susceptible to UV light and freeze/thaw treatment. In addition M. smegmatis Δhup is four times more susceptible to the action of the front-line antibiotic isoniazid. Although the complete molecular function of Hup has not yet been determined, this work demonstrates that Hup does have a role in the structure of the cell envelope and in the resistance to some environmental stresses.
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Details
- Title
- Stress survival in Mycobacterium tuberculosis and Mycobacterium bovis and the role of hup in Mycobacterium smegmatis
- Creators
- Danelle Whiteford
- Contributors
- John L Dahl (Chair)John Nilson (Committee Member)Philip Fowler Mixter (Committee Member) - Washington State University, School of Molecular BiosciencesJohn Jason Wyrick (Committee Member) - Washington State University, School of Molecular BiosciencesMichael J. Smerdon (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Molecular Biosciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 182
- Identifiers
- 99901055134001842
- Language
- English
- Resource Type
- Dissertation