Glycine betaine and polar lipid composition in halophilic archaebacteria in response to growth in different salt concentrations

Examples of halophilic archaebacteria contain low levels of between 1 and 20 mM trimethyl glycine (glycine betaine). In disrupted cell preparations, the glycine betaine is associated with the membrane fraction and is not detectable in cell supernatants. Cells of Natronococcus occultus grown in different salt concentrations show an increase in cell-associated glycine betaine along with an increase in the ratio of phosphatidyl glycerophosphate (PG) to phosphatidyl glycerol (PG) in the cell membrane.