TABLE 1.
Initial rates of glycine betaine uptake in L. lactis IL1403 and MG1363 grown in media of different osmotic strengths and assayed under conditions of low and high osmolarity
| Growth mediuma | Presence of 500 mM KCl in assay buffer | Avg activityb (nmol
min−1 mg−1 of protein) ± SD
|
|
|---|---|---|---|
| IL1403 | MG1363 | ||
| CDM − proline | − | <0.1 | 5 ± 1 |
| CDM − proline + 500 mM KCl | − | 3 ± 0.5 | 20 ± 2 |
| CDM | − | <0.1 | 1 ± 0.5 |
| CDM + 500 mM KCl | − | 1.5 ± 0.5 | 11 ± 2 |
| CDM − proline | + | 11 ± 2 | 24 ± 2 |
| CDM − proline + 500 mM KCl | + | 183 ± 30 | 87 ± 14 |
| CDM | + | 18 ± 3 | 5 ± 0.5 |
| CDM + 500 mM KCl | + | 131 ± 19 | 84 ± 9 |
| GM17 | − | <0.1 | 3 ± 1 |
| GM17 + 500 mM KCl | − | <0.1 | 8 ± 2 |
| GM17 | + | 10 ± 1 | 10 ± 2 |
| GM17 + 500 mM KCl | + | 9 ± 1 | 52.3 ± 11 |
a
CDM contains 675 mg of proline per liter. In the case of GM17, 0.5% glucose was added to the complex broth M17.
b
Presented are initial rates of glycine betaine uptake. The data are for duplicate experiments.