14 research outputs found
Loss of Social Behaviours in Populations of Pseudomonas aeruginosa Infecting Lungs of Patients with Cystic Fibrosis
Pseudomonas aeruginosa, is an opportunistic, bacterial pathogen causing persistent and frequently fatal infections of the lung in patients with cystic fibrosis. Isolates from chronic infections differ from laboratory and environmental strains in a range of traits and this is widely interpreted as the result of adaptation to the lung environment. Typically, chronic strains carry mutations in global regulation factors that could effect reduced expression of social traits, raising the possibility that competitive dynamics between cooperative and selfish, cheating strains could also drive changes in P. aeruginosa infections. We compared the expression of cooperative traits - biofilm formation, secretion of exo-products and quorum sensing (QS) - in P. aeruginosa isolates that were estimated to have spent different lengths of time in the lung based on clinical information. All three exo-products involved in nutrient acquisition were produced in significantly smaller quantities with increased duration of infection, and patterns across four QS signal molecules were consistent with accumulation over time of mutations in lasR, which are known to disrupt the ability of cells to respond to QS signal. Pyocyanin production, and the proportion of cells in biofilm relative to motile, free-living cells in liquid culture, did not change. Overall, our results confirm that the loss of social behaviour is a consistent trend with time spent in the lung and suggest that social dynamics are potentially relevant to understanding the behaviour of P. aeruginosa in lung infections
Loss of social behaviours in populations of Pseudomonas aeruginosa infecting lungs of patients with cystic fibrosis.
Pseudomonas aeruginosa, is an opportunistic, bacterial pathogen causing persistent and frequently fatal infections of the lung in patients with cystic fibrosis. Isolates from chronic infections differ from laboratory and environmental strains in a range of traits and this is widely interpreted as the result of adaptation to the lung environment. Typically, chronic strains carry mutations in global regulation factors that could effect reduced expression of social traits, raising the possibility that competitive dynamics between cooperative and selfish, cheating strains could also drive changes in P. aeruginosa infections. We compared the expression of cooperative traits - biofilm formation, secretion of exo-products and quorum sensing (QS) - in P. aeruginosa isolates that were estimated to have spent different lengths of time in the lung based on clinical information. All three exo-products involved in nutrient acquisition were produced in significantly smaller quantities with increased duration of infection, and patterns across four QS signal molecules were consistent with accumulation over time of mutations in lasR, which are known to disrupt the ability of cells to respond to QS signal. Pyocyanin production, and the proportion of cells in biofilm relative to motile, free-living cells in liquid culture, did not change. Overall, our results confirm that the loss of social behaviour is a consistent trend with time spent in the lung and suggest that social dynamics are potentially relevant to understanding the behaviour of P. aeruginosa in lung infections
The social evolution of pseudomonas aeruginosa in the cystic fibrotic lung
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
The social evolution of pseudomonas aeruginosa in the cystic fibrotic lung
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
The percentage of cells in microtitre culture existing in biofilm of the four <i>P. aeruginosa</i> isolate categories.
<p>Data shown as untransformed averages of five replicates per isolate per category ±SE.</p
Pyocyanin production of the four <i>P. aeruginosa</i> isolate categories.
<p>Data shown as untransformed averages of five replicates per isolate per category ±SE.</p
A table summarising statistical analyses and trends in expression over time across all traits.
<p>A table summarising statistical analyses and trends in expression over time across all traits.</p
The production of ezymes protease (a) and elastase (b) of the four <i>P. aeruginosa</i> isolate categories.
<p>Protease and elastase activity calculated as <i>A</i><sub>440</sub>/<i>A</i><sub>600</sub> and <i>A</i><sub>495</sub>/<i>A</i><sub>600</sub>, respectively. Data shown as untransformed averages of five replicates per isolate per category ±SE.</p