Phage Fate: Infection Dynamics and Outcomes in a Marine Virus - Host System

Persistent Link:
http://hdl.handle.net/10150/556856
Title:
Phage Fate: Infection Dynamics and Outcomes in a Marine Virus - Host System
Author:
Howard-Varona, Cristina
Issue Date:
2015
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release after 31-May-2016
Abstract:
Viruses infecting bacteria (phages) are the most abundant and ubiquitous entities on Earth and likely critical to any ecosystem, as they influence nutrient cycling, mortality and evolution. Ultimately, their impact depends on whether phage—host interactions lead to intracellular phage coexistence (temperate phage) or cell death (lytic phage). Temperate phages in the lysogenic cycle replicate their genome (either integrated into the host chromosome or extrachromosomally), until induced to become lytic, when they create and release progeny via cell lysis. While knowledge on lytic versus lysogenic outcomes is vast, it largely derives from few model systems that underrepresent natural diversity. Further, less is known about the efficiency of phage—host interactions and the regulation of optimal versus sub-optimal lytic infections, which are predicted as relevant under environmental (nutrients, temperature) and host (availability, density) conditions that are common in the ocean. In this dissertation I characterize the phage—host interactions in a new marine model system, phage ϕ38:1 and its Cellulophaga baltica bacterial host, member of the ubiquitous Bacteroidetes phylum. First, I show ϕ38:1’s ability to infect numerous, genetically similar strains of the C. baltica species, two of which display contrasting infection outcomes–lytic versus sub-optimally lytic or lysogenic on the original versus alternative hosts, respectively. Second, I collaboratively apply new gene marker-based approaches (phageFISH and geneELISA) to study ϕ38:1’s infection at the single-cell level and show that it is sub-optimal on the alternative host, rather than lysogenic. Third, I collaboratively develop whole-genome transcriptome datasets for ϕ38:1 infecting both, the optimal and sub-optimal hosts, to characterize the cellular response to infection and hypothesize potential transcriptional and post-transcriptional regulation of the sub-optimal infection. Together, these findings advance our knowledge of naturally-occurring phage—host interactions with a focus on nearly-unstudied sub-optimal infections.
Type:
text; Electronic Dissertation
Keywords:
Bacteriophage; Efficient lytic; Inefficient lytic; Phage-host interactions; Transcriptomics; Molecular & Cellular Biology; Bacteria
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Molecular & Cellular Biology
Degree Grantor:
University of Arizona
Advisor:
Sullivan, Matthew B.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titlePhage Fate: Infection Dynamics and Outcomes in a Marine Virus - Host Systemen_US
dc.creatorHoward-Varona, Cristinaen
dc.contributor.authorHoward-Varona, Cristinaen
dc.date.issued2015en
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en
dc.description.releaseRelease after 31-May-2016en
dc.description.abstractViruses infecting bacteria (phages) are the most abundant and ubiquitous entities on Earth and likely critical to any ecosystem, as they influence nutrient cycling, mortality and evolution. Ultimately, their impact depends on whether phage—host interactions lead to intracellular phage coexistence (temperate phage) or cell death (lytic phage). Temperate phages in the lysogenic cycle replicate their genome (either integrated into the host chromosome or extrachromosomally), until induced to become lytic, when they create and release progeny via cell lysis. While knowledge on lytic versus lysogenic outcomes is vast, it largely derives from few model systems that underrepresent natural diversity. Further, less is known about the efficiency of phage—host interactions and the regulation of optimal versus sub-optimal lytic infections, which are predicted as relevant under environmental (nutrients, temperature) and host (availability, density) conditions that are common in the ocean. In this dissertation I characterize the phage—host interactions in a new marine model system, phage ϕ38:1 and its Cellulophaga baltica bacterial host, member of the ubiquitous Bacteroidetes phylum. First, I show ϕ38:1’s ability to infect numerous, genetically similar strains of the C. baltica species, two of which display contrasting infection outcomes–lytic versus sub-optimally lytic or lysogenic on the original versus alternative hosts, respectively. Second, I collaboratively apply new gene marker-based approaches (phageFISH and geneELISA) to study ϕ38:1’s infection at the single-cell level and show that it is sub-optimal on the alternative host, rather than lysogenic. Third, I collaboratively develop whole-genome transcriptome datasets for ϕ38:1 infecting both, the optimal and sub-optimal hosts, to characterize the cellular response to infection and hypothesize potential transcriptional and post-transcriptional regulation of the sub-optimal infection. Together, these findings advance our knowledge of naturally-occurring phage—host interactions with a focus on nearly-unstudied sub-optimal infections.en
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectBacteriophageen
dc.subjectEfficient lyticen
dc.subjectInefficient lyticen
dc.subjectPhage-host interactionsen
dc.subjectTranscriptomicsen
dc.subjectMolecular & Cellular Biologyen
dc.subjectBacteriaen
thesis.degree.namePh.D.en
thesis.degree.leveldoctoralen
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineMolecular & Cellular Biologyen
thesis.degree.grantorUniversity of Arizonaen
dc.contributor.advisorSullivan, Matthew B.en
dc.contributor.committeememberFane, Bentley A.en
dc.contributor.committeememberNagy, Lisa M.en
dc.contributor.committeememberGutenkunst, Ryan N.en
dc.contributor.committeememberSullivan, Matthew B.en
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