H NMR-based metabolic profile of Lactobacillus salivarius under osmotic stress

摘要

In their natural habitats and application environments, lactic acid bacteria are often exposed to osmolarity changes. In this study, the ~1H nuclear magnetic resonance spectroscopy-based intracellular metabolite profiles of Lactobacillus salivarius under osmotic growth conditions are characterized and recognized. New characteristic peaks of compatible compounds, such as betaine, carnitine, and choline were detected, and the cytoplasmic concentrations of proline and aspartate increased dramatically when the osmolarity was raised from about 0.40 to 1.84osmol/kg by adding 0.8 mol/l NaCl to the growth medium. 2-Aminobutyrate, pyruvate, glycine, trimethylamine-N-oxide, and acetylcholine were detected only under anaerobic hyperosmotic conditions, while 2-oxoglutarate, tyrosine, glutamine, and glutamate were detected only under aerobic hyperosmotic conditions, which suggested that oxygen also has a non-negligible effect on osmotic response in L. salivarius CGMCC 3606.