title: Increase of the ATP-dependent phosphoenolpyruvate carboxykinase activity in Sinorhizobium meliloti (Rhizobium meliloti) during hypothermic environmental conditions.
abstract: Sinorhizobium meliloti growth is affected when the incubation temperature is lower than 22 degrees C. In culture media containing glucose or fructose (1%, w/v), the doubling time at 19 degrees C was about 6.25 h during the exponential growth phase, while it was 2.75 h at 30 degrees C; at 17 degrees C it was three-fold higher than at 30 degrees C. Modifications in the bacterial metabolism explain the doubling time increase when bacteria are incubated at low temperature. We determine here, the phosphoenolpyruvate carboxykinase (PEPCK) activity increases when S. meliloti cells first grown at 30 degrees C are shifted at 17 degrees C and incubated for 10 h at this low temperature; we noted the PEPCK activity was three-fold higher in cells incubated in media containing glucose and shifted from 30 to 17 degrees C than in cells maintained at 30 degrees C, while it was only 1.5-fold higher in cells grown in media containing fructose.
authors.affiliation: Laboratoire de Biotechnologie Microbienne, IUT Génie Biologique, Amiens, France.
authors.forename: I
authors.initials: I
authors.lastname: Adt
authors.forename: B
authors.initials: B
authors.lastname: Courtois
authors.forename: J
authors.initials: J
authors.lastname: Courtois
mesh_terms: D003080:Cold Temperature; D003470:Culture Media; D005947:Glucose / Q000494:pharmacology; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000096:biosynthesis*; D016962:Sinorhizobium meliloti / Q000201:enzymology*
chemical_list: D003470:Culture Media; D019764:Phosphoenolpyruvate Carboxykinase (ATP); D005947:Glucose