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Investigating the Diversity and Evolution of Temperate Actinobacteriophages
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Investigating the Diversity and Evolution of Temperate Actinobacteriophages. |
| 개인저자 | Mavrich, Travis Nathaniel. |
| 단체저자명 | University of Pittsburgh. Dietrich School Arts and Sciences. |
| 발행사항 | [S.l.]: University of Pittsburgh., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 384 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-03B. Dissertation Abstract International |
| ISBN | 9781085746328 |
| 학위논문주기 | Thesis (Ph.D.)--University of Pittsburgh, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
Advisor: Hatfull, Graham F. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Bacteriophages (phages) are viruses that infect bacteria, and they have been evolving for billions of years to combat the hosts they infect as well as other phages in the environment. Many phages are temperate, and after infection they may remain in the host as a prophage, forming a lysogen instead of initiating lytic growth. Lysogeny presents unique challenges and benefits, and as a result temperate phages impact their environment differently than obligately lytic phages. Although temperate phages are diverse, many paradigms about their lifestyle and evolution have been derived from small collections of phages representing limited and ill-defined genetic diversity. Therefore, I have investigated a large collection of phages infecting hosts in the phylum Actinobacteria to expand our understanding of temperate phage diversity and evolution. First, I show that in contrast to obligately lytic phages, temperate phages evolve within two evolutionary modes that are characterized by different degrees of gene content flux and that vary by the type of temperate phage and its bacterial host. Second, I characterize extrachromosomal Mycobacterium prophages that utilize partitioning systems to maintain lysogeny, which are not commonly reported. I show that these prophages exhibit partition-mediated incompatibility and that components of this system evolve under different selective pressures possibly to avoid this instability. Third, I characterize Bifidobacterium prophages and explore how they interact with their hosts. Some of these prophages utilize a unique integration site and encode a shufflon system. This shufflon may control host range and is the first to be reported in actinobacteriophages. Last, I examine the evolution of a Mycobacterium prophage immunity system. This regulatory circuit enables prophages to control expression of lytic genes, maintaining lysogeny and defending against superinfection. I show that closely-related phages with diverging immunity systems generate a complex immunity network and gaining virulence to escape this network is difficult. Overall, this research has broadened our understanding of temperate phage diversity and evolution, and it has identified genetic systems that can be used to develop new genetic tools. |
| 일반주제명 | Molecular biology. Microbiology. Bioinformatics. |
| 언어 | 영어 |
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: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
