Proteins variations in Listeria monocytogenes exposed to high salinities.
Listeria monocytogenes Scott A grown in the minimal chemically defined medium M6LT was challenged to a concentration of either 35 or 65 g l(-1) of NaCl for 1 h in the presence of a [35S]cysteine-[35S]methionine labelling mix. The protein patterns were analysed by 2D-electrophoresis in the two conditions and isoosmotic condition (5 g l(-1) of NaCl in M6LT). A great number of proteins which were synthesized under isoosmotic conditions were either completely repressed or expressed at a reduced level, at 65 g l(-1) and to a lesser extent at 35 g l(-1) of NaCl. At 35 g l(-1) of NaCl, six proteins were up-regulated, five proteins showed no change in expression level and five were repressed. Among the proteins up-regulated at 35 g l(-1) of NaCl, a single one (18.7 kDa, pI 5.05) was up-regulated at 65 g l(-1) too. We observed 21 proteins which were repressed at 65 g l(-1) of NaCl, among which 11 completely disappeared. Some of the up-regulated proteins have characteristics of molecular weight and isoelectric point close to those of stress proteins reported elsewhere: the protein induced both at 35 and 65 g l(-1) might correspond to a previously proposed universal stress protein of Listeria. Some proteins which were repressed at 65 g l(-1) have molecular weights close to those of virulence proteins.
Esvan
H
H
Laboratoire de Microbiologie et Immunologie, UPRES EA 1254, Faculté de Pharmacie, Rennes, France.
Minet
J
J
Laclie
C
C
Cormier
M
M
D001426:Bacterial Proteins / Q000096:biosynthesis*; D008089:Listeria monocytogenes / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*
D001426:Bacterial Proteins; D012965:Sodium Chloride