FIG. 2.

Representative ¹³C NMR spectra from salt-stressed cultures (0.5 M NaCl) of S. meliloti 102F34 grown to early (A) and late (B) exponential phases in LAS medium without or with one of the following osmoprotectants (1 mM): trehalose, maltose, cellobiose, turanose, gentiobiose, or palatinose. (C) Spectrum from a stressed culture grown to late exponential phase in LAS with 0.5 M NaCl plus 1 mM thiodiglucoside. All of the spectra were obtained from a defined amount of cells (about 2 × 10¹² CFU). Sample preparation and NMR analysis were performed as previously described (56). Resonances from endogenously synthesized glutamate (g), the dipeptide NAGGN (d), and trehalose (t), as well as exogenously supplied thiodiglucoside (s), are indicated for points at which these compounds were accumulated as cytosolic osmolytes.