Effects of Lysogeny on Interactions between Bacteria and C. elegans Restricted; Files Only

Abstract

Temperate bacteriophages are viruses that infect and replicate within bacterial cells and have the capacity to form lysogens. Lysogeny occurs when the genome of a bacteriophage integrates with its host bacteria’s DNA and replicates along with the bacteria without inducing lysis. Lysogenic conversion can have significant effects on the characteristics of the host cell. One previously observed trait of lysogenic conversion is non-susceptibility to superinfection by the same phage (superinfection immunity), but prophage integration has been shown to have impacts on many bacterial characteristics. The changes to bacterial phenotypes that accompany infection with a temperate bacteriophage are wide-ranging and can be drastic. Lysogenic conversion may therefore significantly impact bacterial interactions. Little work has been published on the effects of lysogeny on interactions between bacteria and their host organisms. The potential implications for changes to microbial competition are of particular interest in this project. We first investigated the infection dynamics of three bacteriophages with their host strains of Ochrobactrum bacteria, a known colonizer of the C. elegans gut. Next, potential lysogens formed from infection by temperate phage were isolated and further tested to confirm integration of prophage into the host genome. Once lysogeny was confirmed, we carried out choice assays and colonization experiments to examine whether lysogenic conversion altered interactions between bacteria and their host organisms, in this case C. elegans. The results of these experiments provide evidence that lysogeny may provide a competitive advantage in host-associated microbial communities. This work demonstrates the role of viruses in influencing host ecology not only through lysis, but through long-term integration and phenotypic modification.

Table of Contents

Introduction/Background……………………………………………………………………………….1

             What is a Lysogen……………………………………………………………………………….1

             Previous work with lysogens………………………………………………………………2

Aims and Hypothesis……………………………………………………….……………………………..4

Methods……………..………………………………………………………………………………………....5

             Aim 1 methods…………………………………………………………………………………..10

             Aim 2 methods…………………………………………………………………………………..12

             Aim 3 methods…………………………………………………………………………………..15

Results…………………………………………………………………………………………………………..19

             Aim 1 results………………………………………………………………………………………19

             Aim 2 results………………………………………………………………………………………21

             Aim 3A results……………………………………………………………………………………25

             Aim 3B results……………………………………………………………………………………27

Discussion……………………………………………………………………………………………………..30

About this Honors Thesis

Rights statement

• Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.

School	Emory College
Department	Biology
Degree	B.S.
Submission	Honors Thesis
Language	English
Research Field	Biology, Microbiology Biology, Ecology
Keyword	Gut colonization Host-microbe interactions Microbial competition Microbial ecology Lysogeny Phage–host dynamics
Committee Chair / Thesis Advisor	Nic Vega, Emory University
Committee Members	Guy Benian, Emory University Levi Morran, Emory University

Last modified

Primary PDF

Thumbnail	Title	Date Uploaded	Actions
	File download under embargo until 28 November 2026	2026-04-08 09:05:20 -0400	File download under embargo until 28 November 2026

Supplemental Files

Thumbnail	Title	Date Uploaded	Actions