An engineering approach to uncover interactions between bacteriophages, bacteria and mammalian cells
Abstract/Contents
- Abstract
- The hypothesis driving my thesis is that a major role that bacterial viruses (bacteriophages) may play in the body is to collaborate with the host immune environment to clear a bacterial infection. To probe this question, the existing techniques that can be applied to study bacteria:bacteriophage interactions such as viral particle-based plaque assays are limited to measurements at single points in time and for a bulk population of bacteria and viruses. A relevant experimental model for observing phage-immune interactions will be tripartite: the simultaneous observation of bacteriophages within host bacteria phagocytosed by immune cells. In this thesis, I present three projects that probe how bacteriophages influence the success of bacterial infections of immune cells. In the first, I develop a new method to multiplex the engineering of fluorescent life-cycle reporters into the lysogenic lambda phage. These reporter phages are used to create engineered E. coli lysogens which are infected into macrophages and tracked with live-cell imaging to study prophage induction at the single-cell level. Next, I demonstrate for the first time that prophages induce from phagocytosed E. coli in 20% of the infected macrophages. Furthermore, through a dual bacterial strain infection strategy, I show that the bacteriophages released from one strain of E. coli are functional and can kill other E. coli within the same macrophages. These prophage induction events occur in phagocytosed E. coli at a 26-fold higher frequency than basal levels, suggesting that a factor in the macrophage environment actively triggers the induction process. Finally, through the use of bacterial single gene knockouts, I demonstrate that the PhoP pathway, which responds to outer membrane stress from magnesium limitation, acidic pH and antimicrobial peptides, is involved in the induction process. I identify the mammalian-produced antimicrobial peptide, mCramp1, to be a novel inducer of bacterial prophage induction mediated by PhoP. This thesis suggests several possible new mechanisms by which bacteriophages function to assist the bacterial-killing activity of macrophages.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Bodner, Katie |
|---|---|
| Degree supervisor | Covert, Markus |
| Thesis advisor | Covert, Markus |
| Thesis advisor | Endy, Andrew D |
| Thesis advisor | Huang, Kerwyn Casey, 1979- |
| Degree committee member | Endy, Andrew D |
| Degree committee member | Huang, Kerwyn Casey, 1979- |
| Associated with | Stanford University, Department of Bioengineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Katie Bodner. |
|---|---|
| Note | Submitted to the Department of Bioengineering. |
| Thesis | Thesis Ph.D. Stanford University 2020. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Katie Bodner
- License
- This work is licensed under a Creative Commons Attribution Non Commercial No Derivatives 3.0 Unported license (CC BY-NC-ND).
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