Table 1.

Intracellular osmolyte concentrations inL. plantarum

OsmolyteOsmolyte concn (nmol/mg of protein) in CDM supplemented witha:
No additions0.8 M KCl1 M lactose1 M sucrose, −GBb
−GB+GB−GB+GB−GB+GB
Glycine betaine0c ND0c 8500c ∼200∼300
Glutamate5736280110∼550∼500∼550
Alanine23186339∼700∼500∼700
Proline7425010∼100<100∼100
Lactose (or derivative)NDNDNDND∼3,800∼3,200ND
Sucrose (or derivative)NDNDNDNDNDND∼3,600
Lactic acid∼70∼65∼40∼65∼1,200∼1,200∼800
  • a Some of the data are from reference5. −GB, no glycine betaine; +GB, glycine betaine added to a final concentration of 2.5 mM; ND, not detectable; ∼, based on NMR data (less precise than HPLC analysis).

  • b Sucrose solutions were contaminated with >100 μM glycine betaine.

  • c 0 by definition because L. plantarum cannot synthesize glycine betaine.