Nutritional modeling of bacterial infections : physiology and metabolism of Pseudomonas aeruginosa during growth in cystic fibrosis sputum
type: CreativeWork
description: The Gram-negative bacterium Pseudomonas aeruginosa is a notorious opportunistic pathogen of individuals with the genetic disease cystic fibrosis (CF). Pseudomonas aeruginosa establishes a chronic infection within the CF lung, where the sputum accumulation characteristic of CF provides a complex and copious growth substrate. P. aeruginosa can grow to high densities in vivo (>10⁹ cells/ml lung sputum), and exacerbations associated with P. aeruginosa high density in vivo growth are primary contributors to CF morbidity and mortality. Surprisingly little is known about the catabolic processes that underlie P. aeruginosa in vivo growth. Unfortunately, nutritional modeling of the CF lung environment in animal models is difficult, as current animal models fail to mimic the sputum accumulation characteristic of CF. In this dissertation, I describe the use of expectorated CF sputum as a P. aeruginosa in vitro growth medium. Using global expression analysis, I show that P. aeruginosa up-regulates genes important for amino acid and lactate metabolism during growth in CF sputum as compared to a laboratory medium. P. aeruginosa also demonstrates enhanced production of the cell-cell communication signal 2-heptyl-3-hydroxy-4-quinolone (the Pseudomonas quinolone signal, PQS), a critical regulator of virulence factor production, during growth in CF sputum. Further, I use chemical analyses of CF sputum samples to develop a defined, synthetic medium that can be used to nutritionally model in vivo conditions. Using this medium, I show that PQS biosynthesis and aromatic amino acid metabolism are intimately linked and that cell-cell communication mediated by PQS is strikingly dependent upon the growth environment of P. aeruginosa. In addition, I demonstrate that P. aeruginosa preferentially consumes specific carbon sources present in the CF sputum milieu during rapid growth. I also describe the use of in vivo-relevant nutrient concentrations to evaluate the potential for P. aeruginosa ana…
abstract: The Gram-negative bacterium Pseudomonas aeruginosa is a notorious opportunistic pathogen of individuals with the genetic disease cystic fibrosis (CF). Pseudomonas aeruginosa establishes a chronic infection within the CF lung, where the sputum accumulation characteristic of CF provides a complex and copious growth substrate. P. aeruginosa can grow to high densities in vivo (>10⁹ cells/ml lung sputum), and exacerbations associated with P. aeruginosa high density in vivo growth are primary contributors to CF morbidity and mortality. Surprisingly little is known about the catabolic processes that underlie P. aeruginosa in vivo growth. Unfortunately, nutritional modeling of the CF lung environment in animal models is difficult, as current animal models fail to mimic the sputum accumulation characteristic of CF. In this dissertation, I describe the use of expectorated CF sputum as a P. aeruginosa in vitro growth medium. Using global expression analysis, I show that P. aeruginosa up-regulates genes important for amino acid and lactate metabolism during growth in CF sputum as compared to a laboratory medium. P. aeruginosa also demonstrates enhanced production of the cell-cell communication signal 2-heptyl-3-hydroxy-4-quinolone (the Pseudomonas quinolone signal, PQS), a critical regulator of virulence factor production, during growth in CF sputum. Further, I use chemical analyses of CF sputum samples to develop a defined, synthetic medium that can be used to nutritionally model in vivo conditions. Using this medium, I show that PQS biosynthesis and aromatic amino acid metabolism are intimately linked and that cell-cell communication mediated by PQS is strikingly dependent upon the growth environment of P. aeruginosa. In addition, I demonstrate that P. aeruginosa preferentially consumes specific carbon sources present in the CF sputum milieu during rapid growth. I also describe the use of in vivo-relevant nutrient concentrations to evaluate the potential for P. aeruginosa ana…
author: Palmer, Kelli Lea, 1981-
language: eng
date published: 2008-12
date modified: 2026-07-24T05:01:24Z
provider: University of Texas
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Texas at Austin

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2152/18214