Osmotic control of glycine betaine biosynthesis and degradation in Rhizobium meliloti

Journal Article · Fri Jul 01 00:00:00 EDT 1988 · J. Bacteriol.; (United States)

OSTI ID:6583370

Smith, L T; Pocard, J A; Bernard, T; Le Rudulier, D

Intracellular accumulation of glycine betaine has been shown to confer an enhanced level of osmotic stress tolerance in Rhizobium meliloti. In this study, the authors used a physiological approach to investigate the mechanism by which glycine betaine is accumulated in osmotically stressed R. meliloti. Results from growth experiments, /sup 14/C labeling of intermediates, and enzyme activity assays are presented. The results provide evidence for the pathway of biosynthesis and degradation of glycine betaine and the osmotic effects on this pathway. High osmolarity in the medium decreased the activities of the enzymes involved in the degradation of glycine betaine but not those of enzymes that lead to its biosynthesis from choline. Thus, the concentration of the osmoprotectant glycine betaine is increased in stressed cells. This report demonstrates the ability of the osmolarity of the growth medium to regulate the use of glycine betaine as a carbon and nitrogen source or as an osmoprotectant. The mechanisms of osmoregulation in R. meliloti and Escherichia coli are compared.

• Research Organization: Univ. of California, Davis (USA)
• OSTI ID: 6583370
• Journal Information: J. Bacteriol.; (United States), Vol. 170:7
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GLYCINE
BIOSYNTHESIS
RHIZOBIUM
BIOLOGICAL STRESS
CARBON 14 COMPOUNDS
COMPARATIVE EVALUATIONS
ENZYME ACTIVITY
ESCHERICHIA COLI
METABOLISM
OSMOSIS
TRACER TECHNIQUES
AMINO ACIDS
BACTERIA
CARBOXYLIC ACIDS
DIFFUSION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
SYNTHESIS
550201* - Biochemistry- Tracer Techniques