FIG. 5.

Effect of osmotic shock on macromolecular synthesis and induction of the lac operon. (A) Strain TL3353 was grown in K medium containing 10 μCi [U-¹⁴C]glucose. At 0 h, the osmolality of the medium was increased with 0.3 M NaCl. Samples were removed from the culture at the indicated time points, and the incorporation of radioactivity into macromolecules was determined as described in Materials and Methods. (B) Strain TL3799 (kdp⁺ proX-phoA/F′ lac⁺) was grown in K medium. At −15 min, the lac operon was induced with 1 mM IPTG; at time 0, the osmolality of the culture was increased with 0.3 M NaCl. The accumulation of β-galactosidase and alkaline phosphatase (in nanomoles per minute per milligram of protein) was determined at the indicated time points, as described in Materials and Methods.