Etude de la réponse à différents stress environnementaux chez Caulobacter crescentus

Student thesis: Doc typesDoctor of Sciences

Abstract

Caulobacter crescentus triggers the secretion of various proteins to adapt to stressful or changing environment. In particular, C. crescentus secretes an extracellular lipoprotein, ElpS, in response to phosphate starvation. Our results demonstrate that ElpS is partially released in the environment dependently on type II secretion system and activates an external alkaline phosphatase activity. Nevertheless, the exact role of ElpS in phosphate mobilization remains unclear. Interestingly, PcoAcc, encoding an putative protein involved in copper resistance, modulates the expression of elpS but physiological relevance of this interaction is still unknown. PcoAcc is encoded on C. crescentus chromosome in operon with a second gene, pcoBcc, which also contains several predicted copper binding domains. Although the exact mechanism is not still entirely described, PcoAcc et PcoBcc are both essential for C. crescentus survival in medium containing copper. Preliminary results suggest that PcoAcc is exported in cell surface and facilitate copper efllux. Deletion of pcoAcc and/or pcoBcc in C. crescentus results in enhanced copper accumulation in bacteria leading to cell death. Reciprocally, mutant strains for pcoAcc are able to remove high amount of copper from contaminated aqueous solutions and can be consequently be used as biosorbents in water treatment.
Date of Award10 Jul 2012
Original languageFrench
Awarding Institution
  • University of Namur
SupervisorJean-Yves Matroule (Supervisor), Éric Depiereux (President), Xavier De Bolle (Jury), Pierre Cornelis (Jury) & Olivera FRANCETIC (Jury)

Cite this

Etude de la réponse à différents stress environnementaux chez Caulobacter crescentus
Le Blastier, S. (Author). 10 Jul 2012

Student thesis: Doc typesDoctor of Sciences