Titre :
|
Escherichia coli and Lactobacillus plantarum responses to osmotic stress
|
Auteurs :
|
I. Poirier ;
P. Marechal ;
C. Evrard ;
P. Gervais
|
Type de document :
|
article/chapitre/communication
|
Année de publication :
|
1997
|
Format :
|
p. 704-709
|
Langues:
|
= Anglais
|
Catégories :
|
Biologie
|
Mots-clés:
|
BACTERIE PATHOGENE
;
STRESS HYDRIQUE
;
MORTALITE
|
Résumé :
|
Escherichia coli and Lactobacillus plantarum were subjected to final water potentials of -5.6 MPa and -11.5 MPa with three solutes: glycerol, sorbitol and NaCl. The water potential decrease was realized either rapidly (osmotic shock) or slowly (20 min) and a difference in cell viability between these conditions was only observed when the solute was NaCl. The cell mortality during osmotic shocks induced by NaCl cannot be explained by a critical volume decrease or by the intensity of the water flow across the cell membrane. When the osmotic stress is realized with NaCl as the solute, in a medium in which osmoregulation cannot take place, the application of a slow decrease in water potential resulted in the significant maintenance of cell viability (about 70-90%) with regard to the corresponding viability observed after a sudden step change to same final water potential (14-40%). This viability difference can be explained by the existence of a critical internal free Naf concentration.
|
Source :
|
Applied Microbiology and Biotechnology, vol.50
|