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|Title: ||Model socialite, problem pathogen: the evolution and ecology of cooperation in the bacterium Pseudomonas aeruginosa|
|Authors: ||Ross-Gillespie, Adin|
|Issue Date: ||2008|
|Publisher: ||The University of Edinburgh|
|Abstract: ||In recent decades we have learned that cooperation is an important and pervasive
feature of microbial life. This revelation raises exciting possibilities. On the one
hand, we can now augment our understanding of how social phenomena evolve by
using microbial model systems to test our theories. On the other hand, we can use
concepts from social evolution to gain insight into the biology of the microbes we
hope to control or kill.
In this thesis I explore both possibilities. First, I consider the theoretical problem of
how and when microbial cooperation might be subject to frequency- and densitydependence.
Formerly, vague theory and a scant, sometimes contradictory empirical
literature made it unclear when such patterns could be expected. Here, I develop
theory tailored to a microbial context, and in each case, I test key predictions from
the theory in laboratory experiments, using as my model trait the production of
siderophores by the bacterium Pseudomonas aeruginosa.
Secondly, I consider the ecological consequences of cooperator-cheat dynamics in
the context of an infection. Specifically, I use experimental infections of diverse host
models to investigate the role of two cooperative traits, siderophore production and
quorum sensing, in the pathogenesis of P. aeruginosa. When a successful infection
requires cooperation among pathogens, theory predicts that conflict among coinfecting
strains can undermine cooperation and hence decrease virulence; whereas,
in the absence of cooperation, conflict could lead to heightened exploitation and
hence increased virulence. This exciting idea has received little empirical attention to
date but here I address this using multiple pathogen strains, multiple social traits, and
multiple model hosts.|
|Appears in Collections:||Biological Sciences thesis and dissertation collection|
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