Date of Award

January 2025

Document Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Eduardo E. Groisman

Abstract

Magnesium (Mg²⁺) is essential for bacterial physiology, contributing to membrane stability, nucleic acid neutralization, and enzymatic activity. For pathogenic bacteria such as Salmonella enterica serovar Typhimurium, Mg²⁺ limitation is a common stress encountered during infection, particularly within the phagosome, where the host actively restricts access to divalent cations as part of nutritional immunity. Commensal species such as Bacteroides thetaiotaomicron, which reside in the intestinal lumen, are likely to experience different Mg²⁺ levels due to factors such as host dietary intake, host secretions, and microbial competition. Whereas enteric pathogens such as S. Typhimurium activate the PhoP/PhoQ system in response to Mg²⁺ limitation, the strategies used by commensal gut bacteria to withstand Mg²⁺ stress remain unclear. As major contributors to polysaccharide degradation, immune modulation, and other host-associated processes, Bacteroides species play a pivotal role in promoting gut health. Enhancing their colonization and persistence therefore holds significant therapeutic potential. In this study, we examine the genetic determinants that promote the survival of Bacteroides thetaiotaomicron under conditions of cytoplasmic Mg²⁺ stress, identifying candidate factors that may contribute to its fitness within the gut environment.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 05/01/2028

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