Spiteful Weapons and the Environmental Dependence of Phage Open Access

Worthy, Andrew (Spring 2020)

Permanent URL: https://etd.library.emory.edu/concern/etds/bv73c164v?locale=en
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Abstract

The assembly of bacteria-phage communities occurs in an environmental context. To delineate how temperate phage-bacteria dynamics are affected by their environment, phage infection parameters were estimated in varying nutrient and temperature conditions. Models of lysogen versus phage-sensitive bacterial competitions in these same conditions were then formed from the parameter estimates and were used to predict competition outcomes. The empirical models accurately described qualitative competition outcomes and predicted a phage-resistant subpopulation in one of the putatively phage-sensitive strains. Moreover, this study shows environmentally dependent phage-bacteria dynamics can direct competition outcomes when given enough time before the bacterial populations reach stationary phase. 

Table of Contents

Table of Contents

Introduction ........................................................................................................................................................ 1

Methods .............................................................................................................................................................. 3

Table 1: Bacterial strains and phage used in this study. ...........................................................................................4

Figure 1: Measuring Latent Period, Adsorption Rate, and Burst Size........................................................................4

Results................................................................................................................................................................. 8

Table 2: Latent Period, Adsorption Rate, and Burst Size Estimates ..........................................................................9

Figure 2: Probability of Lysogen Formation. .............................................................................................................9

Table 3: Lytic Induction Rate (CFU-1 • hour-1)..........................................................................................................10

Figure 3: Competition Models and Experimental Data. ..........................................................................................11

Figure 4: Modelling a Phage-Resistant Subpopulation. ..........................................................................................12

Discussion.......................................................................................................................................................... 12

Figure 5: Assaying Phage-Resistance and Attempted Recovery. ............................................................................14

Figure 6: Improving the Competitions Based on the Model....................................................................................16

References......................................................................................................................................................... 18 

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