Skip to Main content Skip to Navigation
Theses

Pseudomonas adaptation to stress factors : role of membrane lipids and Pseudomonas fluorescens response to NO2

Abstract : The high distribution of Pseudomonas fluorescens group is linked to its ability to adapt to stress factors. This work goaled the response of an airborne P. Fluorescens MFAF76a, and its clinical standard P. Fluorescens MFN1032 to environmental changes in order to refine the specific adaptation of airborne bacteria. First the HPTLC-MALDI TOF MSI tool defined glycerophospholipid (GP) composition of both strains. In stationary growth phase, an unknown GP, in short UGP, was found and seemed to be involved in temperature adaptation for the clinical strain. After exposure to 0. 1, 5 and 45 ppm concentrations, the bacterial response to NO2 was defined through motility, biofilm formation, antibiotic resistance and expression of several chosen target genes. While no change in parameters was seen in bacteria exposed to 0. 1 and 5 ppm of NO2, several alterations were occurred with a bacterial exposure to 45 ppm. NO2 seemed to bias the UGP production, reduced P. Fluorescens swim and decreased swarm only for MFN1032 strain. Biofilm formed by NO2-treated MFAF76a showed increased maximum thickness, with no change in c-di-GMP intracellular level. Expression of the hmp-homologue gene involved in NO detoxification was upregulated in response to NO2, suggesting a possible common pathway between NO and NO2 detoxification. Finally, NO2 was found to increase bacterial resistance to ciprofloxacin and chloramphenicol. Thus the resistance nodulation cell division (RND) MexEF-OprN efflux pump encoding genes were highly upregulated in both strains. Together these findings implement the first model of bacterial response to NO2 toxicity and the role(s) of GP in bacterial adaptation to environmental changes.
Complete list of metadatas

Cited literature [264 references]  Display  Hide  Download

https://hal-normandie-univ.archives-ouvertes.fr/tel-02367336
Contributor : Cécile Duclairoir Poc <>
Submitted on : Sunday, November 17, 2019 - 6:57:18 PM
Last modification on : Thursday, November 21, 2019 - 1:32:34 AM
Long-term archiving on: : Tuesday, February 18, 2020 - 3:35:48 PM

File

Manuscrit de thèse Final 15 0...
Files produced by the author(s)

Identifiers

  • HAL Id : tel-02367336, version 1

Citation

Tatiana Kondakova. Pseudomonas adaptation to stress factors : role of membrane lipids and Pseudomonas fluorescens response to NO2. Bacteriology. Université de Rouen, 2015. English. ⟨tel-02367336⟩

Share

Metrics

Record views

38

Files downloads

50