TABLE 2.
Comparative effects of glycine betaine, ectoine, and various exogenous polysaccharides on the growth of S. meliloti 102F34 at high osmolaritiesa
| Putative osmoprotectant added | Growth parametersb in LAS with:
|
|||||
|---|---|---|---|---|---|---|
| No osmoticum
|
0.5 M NaCl
|
0.8 M Mannitolc
|
||||
| DT (h) | ODmax | DT (h) | ODmax | DT (h) | ODmax | |
| None | 4.0 | 2.0 | 20.0 | 1.0 | 18.0 | 0.9 |
| Sucrose | 4.0 | 2.0 | 8.0 | 2.0 | 8.0 | 1.8 |
| Glycine betaine | 3.9 | 2.0 | 8.0 | 2.0 | 8.0 | 2.1 |
| Ectoine | 4.0 | 1.9 | 7.5 | 1.8 | 9.0 | 1.8 |
| Trehalose | 3.9 | 2.1 | 8.0 | 2.0 | 8.5 | 2.1 |
| Maltose | 4.0 | 2.0 | 8.5 | 2.0 | 8.5 | 1.9 |
| Cellobiose | 4.2 | 1.9 | 8.0 | 1.9 | 9.3 | 1.8 |
| Turanose | 4.1 | 2.0 | 8.0 | 2.0 | 9.0 | 1.9 |
| Gentiobiose | 4.0 | 2.0 | 7.0 | 1.9 | 8.5 | 2.1 |
| Palatinose | 4.1 | 1.9 | 7.0 | 1.9 | 8.5 | 1.8 |
| Lactosed | 4.0 | 2.0 | 20.0 | 1.0 | 18.0 | 0.9 |
| Thiodiglucoside | 3.9 | 2.0 | 20.2 | 1.0 | 18.0 | 0.9 |
| Raffinose | 3.9 | 2.0 | 20.5 | 1.1 | 18.0 | 0.9 |
| Maltotriose | 3.9 | 1.8 | 11.0 | 2.0 | 10.5 | 1.9 |
| Maltotetraose | 4.0 | 1.9 | 20.0 | 1.1 | 18.0 | 0.9 |
a
Cultures were grown in LAS without or with an osmoticum (0.5 M NaCl or 0.8 M mannitol) in the presence of 1 mM of the indicated putative osmoprotectant.
b
Growth parameters are expressed as the doubling time (DT) (in hours per generation) and the maximal optical density (ODmax), which was measured at 570 nm at stationary phase.
c
LAS with 0.8 M mannitol is iso-osmotic with LAS plus 0.5 M NaCl [980 mosm/kg H2O (20)].
d
Similar results were obtained with 1 mM melibiose and lactulose.