Contribution à l'étude des fonctions d'OprF dans l'adaptation des bactéries du genre Pseudomonas à l'environnement

ROUEN-BU Sciences (764512102) / SudocSudocFranceF

Outer membrane modifications of Pseudomonas fluorescens MF37 in response to hyperosmolarity.

International audienceThe effect of hyperosmotic condition on the outer membrane protein (Omp) composition of Pseudomonas fluorescens was investigated by proteomic analyses. The abundances of 12 proteins, including porins, lipoproteins, and the flagella subunit FliC, were modified. This was at least partly explained by altered gene expression, as shown by mRNA level study. In agreement with Omp changes, hyperosmotic condition resulted in vesicle formation and modifications of mobility and antibiotic susceptibility

The Major Outer Membrane Protein Oprf is Required for Rhamnolipid Production in Pseudomonas aeruginosa

International audienceThe OprF porin is the major outer membrane protein of bacteria belonging to the Pseudomonas genus, and is partially exposed on the cellular surface. A study based on the comparison between P. aeruginosa H103 and its oprFdeficient mutant led to the finding that the absence of OprF abolished swarming but not swimming and twitching motilities. These phenotypes were explained at least in part by the inability of the oprF mutant to produce biosurfactant rhamnolipids. The levels of mRNAs encoding the rhamnolipid biosynthetic enzymes RhlA and RhlB were strongly decreased in the absence of OprF, indicating that rhamnolipid production was impaired at the transcriptional level. We suggest that the presence of OprF in the outer membrane of P. aeruginosa is required for environments colonization, making thus OprF a serious target for limiting P. aeruginosa spreading in case of cystic fibrosis

The absence of OprF increased biofilm formation through variation of the c- di-GMP level in Pseudomonas aeruginosa

International audienceIntroduction Pseudomonas aeruginosa is well known to be a human opportunistic pathogen able to adapt to many environmental conditions. The first cellular structure in contact with the environment is the outer membrane. In Pseudomonas genus, OprF is the major outer membrane protein. It is an aspecific porin allowing the diffusion of several types of small polar molecules. OprF is also a pleiotropic protein involved in other numerous cellular functions, as adhesion on biotic or abiotic surfaces, cell wall resistance and virulence of P. aeruginosa. Through a multiphenotypic study, we show here that the lack of OprF increased biofilm formation through modulation of the c-di-GMP level

The absence of OprF increased biofilm formation through variation of the cdi-GMP level in Pseudomonas aeruginosa.

International audienc

The absence of OprF increased biofilm formation through variation of the cdi-GMP level in Pseudomonas aeruginosa.

International audienc

Full Virulence of Pseudomonas aeruginosa Requires OprF▿

OprF is a general outer membrane porin of Pseudomonas aeruginosa, a well-known human opportunistic pathogen associated with severe hospital-acquired sepsis and chronic lung infections of cystic fibrosis patients. A multiphenotypic approach, based on the comparative study of a wild-type strain of P. aeruginosa, its isogenic oprF mutant, and an oprF-complemented strain, showed that OprF is required for P. aeruginosa virulence. The absence of OprF results in impaired adhesion to animal cells, secretion of ExoT and ExoS toxins through the type III secretion system (T3SS), and production of the quorum-sensing-dependent virulence factors pyocyanin, elastase, lectin PA-1L, and exotoxin A. Accordingly, in the oprF mutant, production of the signal molecules N-(3-oxododecanoyl)-l-homoserine lactone and N-butanoyl-l-homoserine lactone was found to be reduced and delayed, respectively. Pseudomonas quinolone signal (PQS) production was decreased, while its precursor, 4-hydroxy-2-heptylquinoline (HHQ), accumulated in the cells. Taken together, these results show the involvement of OprF in P. aeruginosa virulence, at least partly through modulation of the quorum-sensing network. This is the first study showing a link between OprF, PQS synthesis, T3SS, and virulence factor production, providing novel insights into virulence expression