Skip to Main content Skip to Navigation
Theses

Étude de la composition et de l'assemblage du pore de translocation du système de secretion de type III chez Pseudomonas aeruginosa

Abstract : PSEUDOMONAS AERUGINOSA IS AN OPPORTUNISTIC PATHOGEN FOR HUMANS AND IS ONE OF THE MAJOR AGENTS RESPONSIBLE FOR NOSOCOMIAL INFECTIONS. P. AERUGINOSA, LIKE OTHER GRAM-NEGATIVE PLANT AND ANOMAL PATHOGENS, UTILIZES A TYPE III SECRETION-TRANSLOCATION SYSTEM (TTSS) TO INTOXICATE EUKARYOTIC CELLS. THIS SYSTEM ALLOWS TO THE EXTRACELLULARLY LOCATED BACTERIUM TO INJECT ITS TOXIC PRODUCTS (EFFECTORS) DIRECTLY INTO THE HOST CELL CYTOPLASM. THE SECRETION AND TRANSLOCATION STEPS INVOLVE MORE THAN 20 PROTEINS ASSEMBLED INTO A NEEDLE-LIKE STRUCTURE CALLED INJECTISOMES. COMPONENTS INVOLVED IN EFFECTOR TRANSLOCATION ACROSS THE HOST PLASMA MEMBRANE ARE ENCODED IN THE pcrGVH-popBD OPERON. IN THE LABORATORY, WE HAVE SHOWN THAT THE P. AERUGINOSA CYSTIC FIBROSIS ISOLATE CHA INDUCES TYPE III SECRETION SYSTEM-DEPENDENT ONCOSIS OF PHAGOCYTES. THIS CELLULAR ONCOSIS IS PRECEDED BY THE FORMATION OF PORES INSERTED INTO EUKARYOTICS MEMBRANES. INTERACTION OF P. AERUGINOSA WITH RED BLOOD CELLS (RBC) SHOWED THAT THIS PORES WERE ESTIMATED FROM OSMOPROTECTION EXPERIMENTS TO BE BETWEEN 28 AND 35Å. IN PARALLEL, WE FOUND THAT THERE WAS A SIMULTANEOUS REQUIREMENT FOR ALL THREE PROTEINS, PCRV, POPB, AND POPD, FOR CELL INTOXICATION AND HEMOLYSIS. FRACTIONATION EXPERIMENTS WITH INFECTED RBCs SHOWN THAT ONLY POPB AND POPD FORM THE MEMBRANE-ASSOCIATED CORE OF THE PORE. WE DEMONSTRATED THAT THE ANTI-V ANTIBODIES THROUGH THEIR DIRECT INTERACTION WITH V PROTEINS, INHIBITS BACTERIA-INDUCED HEMOLYSIS, AS IN PCRV MUTANT, BY ACTING AT THE LEVEL OF TYPE III TRANSLOCON ASSEMBLY IN HOST CELL MEMBRANES. THESE RESULTS SUGGESTS THAT PCRV PROTECTIVE ANTIGEN WOULD ACT AS EXTRABACTERIAL CHAPERONES.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00008605
Contributor : Julien Gouré <>
Submitted on : Tuesday, March 1, 2005 - 3:07:23 PM
Last modification on : Friday, November 6, 2020 - 4:11:21 AM
Long-term archiving on: : Friday, September 14, 2012 - 11:30:10 AM

Identifiers

  • HAL Id : tel-00008605, version 1

Collections

UJF | CEA | CNRS | UGA

Citation

Julien Goure. Étude de la composition et de l'assemblage du pore de translocation du système de secretion de type III chez Pseudomonas aeruginosa. Biochimie [q-bio.BM]. Université Joseph-Fourier - Grenoble I, 2005. Français. ⟨tel-00008605⟩

Share

Metrics

Record views

476

Files downloads

1030