Metabolic and Physiological Determinants in Listeria monocytogenes Anaerobic Virulence Regulation

Date of Award


Degree Name

Ph.D. in Biology


Department of Biology


Advisor: Yvonne Sun


In order for enteric pathogens to be successful in causing their infection they must overcome various environmental factors including: low pH, decreased oxygen, high osmolarity, nutrient competition, and host immune system etc. One such pathogen, Listeria monocytogenes (L. monocytogenes), is well known for being extremely adaptable and avoids host immune defenses by causing its infection intracellularly. This unique infection route makes L. monocytogenes an attractive pathogen for gaining further understanding host immune responses to intracellular pathogens. However, the majority of studies involving L. monocytogenes take place in the presence of oxygen, which completely omits the anaerobic phase of gastrointestinal infection. The main goal of this study is to understand the effects of anaerobic growth on L. monocytogenes pathogenesis. Chapter I provides a brief introduction including background information on L. monocytogenes discovery, lifestyle, outbreaks, and pathogenesis. Following the introduction in Chapter II, I give a review on the role of oxygen in the pathogenesis of various other relevant enteric pathogens. Moving into Chapter III, I look at key morphological differences between aerobic and anaerobic growth conditions and explores how exogenous supplementation of key intermediates of the tricarboxylic acid cycle (TCA) affects subsequent pathogenesis. This transitions into Chapter IV, where I explore the role of respiratory activity in priming and sustaining intracellular pathogenesis. And finally, Chapter V evaluates the importance of menaquinone biosynthesis in L. monocytogenes growth and subsequent pathogenesis. Together these data support a regulatory role for metabolic activity in the success of L. monocytogenes infection.


Biology, Microbiology, Listeria, anaerobic, metabolism, respiration, virulence, intracellular growth, bacterial physiology

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Copyright © 2018, author