TABLE 3.
Effects of glycine betaine analogs on growth of salt-stressed L. monocytogenes in the presence of carnitinea
| Added compound(s) | Avg doubling time (h) ± SD for strain:
|
||
|---|---|---|---|
| DP-L1044 | LTG59 | LTS4A | |
| CAR | 31 ± 1 | 9.6 ± 0.3 | NG |
| CAR + DMG | 38 ± 3 | 8.4 ± 0.2 | 47 ± 5 |
| CAR + γBB | 34 ± 1 | 8.6 ± 0.2 | 53 ± 2 |
| CAR + TRI | 49 ± 5 | 8.7 ± 0.1 | NG |
| CAR + TEG | 37 ± 1 | 8.5 ± 0.4 | NG |
| CAR + DMG + γBB | 26 ± 1 | 6.8 ± 0.1 | 24 ± 2 |
| CAR + DMG + TRI | 25 ± 1 | 9.0 ± 0.1 | 65 ± 5 |
| CAR + DMG + TEG | 25 ± 1 | 9.8 ± 0.3 | NG |
| CAR + γBB + TRI | 22 ± 1 | 7.7 ± 0.3 | 41 ± 2 |
| CAR + γBB + TEG | 23 ± 1 | 8.0 ± 0.3 | NG |
| CAR + TRI + TEG | 25 ± 1 | 9.0 ± 0.4 | NG |
a
Values are the averages of three separate experiments. Strains DP-L1044 and LTS4A were grown in modified Pine's medium containing 9% NaCl in order to show differences clearly; strain LTG59 was grown in the same medium but with only 6% NaCl. Abbreviations: CAR, carnitine; DMG, dimethylglycine; γBB, γ-butyrobetaine; TRI, trigonelline; TEG, triethylglycine; NG, no growth observed over 20 days. Carnitine was added at 100 μM; all other compounds were added at 5 mM.