Table 1.

Growth rates and proline, betaine, and total amino acid contents of wild-type and OSM35 cells grown under various conditionsa

Growth conditionμ (h−1)Proline concn (nmol/mg of protein)Betaine concn (nmol/mg of protein)Amino acid concnb(nmol/mg of protein)
wtOSM35wtOSM35wtOSM35wtOSM35
CDM0.610.591012 –c 460490
CDM + NaCl0.430.5145560790
CDM + Pro0.750.761525370470
CDM + Pro + NaCl0.620.5920117750680
CDM + NaCl + Bet0.610.5156530520730
CDM + Pro + NaCl + Bet0.700.541615560510660
  • a The cells were cultivated in the indicated medium. The final concentrations of the various additives were as follows: proline, 5.9 mM; NaCl, 0.3 M; betaine, 1 mM. A volume of culture in exponential phase (A600 = 0.8 to 1) corresponding to 1 mg of protein was filtered, and cytoplasmic content was released by osmotic downshock. Growth rates were determined independently in microplate assays, and the values are the means of triplicate experiments. Amino acid analysis was performed on an amino acid analyzer. Glycine betaine was quantified by HPLC. wt, wild type; Pro, proline; Bet, betaine.

  • b The data represent the sum of the 19 amino acids (with proline) detected by the analysis. Data are the means of duplicate experiments.

  • c –, Value below the detection limit (<2).