Identification of new genes related to osmotic adaptation in Enterococcus faecalis
Résumé
Bidimensional electrophoresis allowed to observe during an hyperosmotic treatment the induction of the synthesis of 96 proteins including 6 general stress proteins. The gsp64 gene, encoding one of them was identified by reverse genetic methods. Transcriptional analysis of gsp64 showed induction when cells were subjected to hyperosmotic, oxidative, heat, acid or detersive treatments. A gsp64- mutant showed a sensibility toward alkaline, ethylic or oxidative stresses. In addition, the screening of a library of insertional mutants allowed the isolation of 9 NaCl-sensitive mutants. Their characterisation led to the identification of 6 distinct loci: mutations affecting genes involved in carbohydrate transport, in amino-acid or peptidoglycan biosynthesis pathways, and genes of unknown function.