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Caractérisation d'activités oxydo-réductases, leurs systèmes de régulation et leur distribution au sein de la population microbienne

Abstract : Reductase activities are widespread among microorganisms. Among these activities, it is possible to distinguish different families based on reduced substrates such as azoreductases that catalyze the reduction of “azo” bounds (N=N) and nitroreductases that catalyze the reduction of nitro group (NO2). This work aims to study the distribution of reductase activities such as nitroreductase and azoreductase in microorganisms using fluorescent substrates. This work aims to evaluate the appropriateness of using these enzyme activities in diagnostic tests for detection or identification of microorganisms sought in a clinical or industrial context. A thorough study of these enzyme activities was performed on two bacterial species: Escherichia coli and Enterococcus faecalis. The study of azoreductase activity focused on a single enzyme (AzoR) in E. coli and 2 enzymes (AzoA and EF0404) in E. faecalis. Concerning nitroreductase activity, three enzymes (NfsA, AzoR and NfsB) have been identified in E. coli while 5 enzymes (AzoA, EF0404, EF1181, EF0648 and EF0655) have been identified as nitroreductases in E. faecalis. The in vivo study in E. coli has highlighted the essential role of AzoR in aerobic azoreductase activity whereas in anaerobic conditions the protein AzoR is involved, but an independent way of the enzyme AzoR, not specifically characterized to date, takes over. The nitroreductase activity of E. coli is due mainly to the proteins NfsA et NfsB
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https://tel.archives-ouvertes.fr/tel-02862797
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Submitted on : Tuesday, June 9, 2020 - 4:42:43 PM
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  • HAL Id : tel-02862797, version 1

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Claire Mercier. Caractérisation d'activités oxydo-réductases, leurs systèmes de régulation et leur distribution au sein de la population microbienne. Microbiologie et Parasitologie. Université Claude Bernard - Lyon I, 2013. Français. ⟨NNT : 2013LYO10025⟩. ⟨tel-02862797⟩

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