Publicação
Metabolic-derived functions during adaptation of E. coli to the mammalian gut
| Resumo: | Mammals harbour a cosmos of microbes in their gastrointestinal tract throughout their life. This dense polymicrobial network is dominated by commensal bacteria that live mostly in harmony with their host. Disruption of this homeostasis is detrimental to nutrient acquisition and overall health of the host. Colonisation is the first step in persistence and/or infection in the GI tract, it is thus essential to understand how in vivo bacteria obtain energy, carbon and nitrogen to sustain their growth and resist elimination. This work focused on a particular species of enteric bacteria, by studying the best characterized Escherichia coli strain. Use of this commensal strain (K-12 MG1655) has been the most prevalent in recent studies, it is well characterised at the genetic level and has been studied in the intestinal environment. This worked was founded on the hypothesis that the establishment of a metabolic landscape compatible with the state and composition of the intestinal environment is an important pressure for E. coli, highlighting from an evolutionary scale the fundamental importance of metabolism for intestinal colonisation. Through the characterization of the genetic basis and the evolutionary and physiological effects of the predominant beneficial mutations during adaptation to the intestinal environment of mice, this work presents mechanistic evidence and novel insights on how bacteria can establish and persist in specific ecological settings of this complex ecosystem. |
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| Autores principais: | Pedro, Miguel Filipe Marques |
| Assunto: | Mamíferos Microbiota E. coli Evolução Metabolismo Teses de mestrado - 2016 |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Mammals harbour a cosmos of microbes in their gastrointestinal tract throughout their life. This dense polymicrobial network is dominated by commensal bacteria that live mostly in harmony with their host. Disruption of this homeostasis is detrimental to nutrient acquisition and overall health of the host. Colonisation is the first step in persistence and/or infection in the GI tract, it is thus essential to understand how in vivo bacteria obtain energy, carbon and nitrogen to sustain their growth and resist elimination. This work focused on a particular species of enteric bacteria, by studying the best characterized Escherichia coli strain. Use of this commensal strain (K-12 MG1655) has been the most prevalent in recent studies, it is well characterised at the genetic level and has been studied in the intestinal environment. This worked was founded on the hypothesis that the establishment of a metabolic landscape compatible with the state and composition of the intestinal environment is an important pressure for E. coli, highlighting from an evolutionary scale the fundamental importance of metabolism for intestinal colonisation. Through the characterization of the genetic basis and the evolutionary and physiological effects of the predominant beneficial mutations during adaptation to the intestinal environment of mice, this work presents mechanistic evidence and novel insights on how bacteria can establish and persist in specific ecological settings of this complex ecosystem. |
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