Fig. 6.

Primer extension analysis of the ectT transcript in V. pantothenticus. (A) DNA sequence of the ectT regulatory region; the arrow shows the 5′ end of the ectT transcript, and the position of the inferred SigB-dependent promoter is indicated. V. pantothenticus cells carrying plasmid pAK14 (ectT′) were grown in SMM to mid-exponential growth phase (OD₅₇₈ of about 1) at 37°C and then subjected to an osmotic up-shift with 0.7 M NaCl (B), a sudden temperature downshift to 15°C (C), or an ethanol shock (4%, vol/vol) (D). The 5′ end of the ectT transcript was determined by a primer extension reaction. (E) Primer extension analysis of the ectT transcript in the heterologous host B. subtilis. The B. subtilis wild-type strain and its sigB mutant derivative strain BLOB22, carrying plasmid pAK14, were grown in SMM to mid-exponential growth phase (OD₅₇₈ of about 1) at 37°C. One culture of each strain was left untreated (−) or subjected to an osmotic up-shift with 0.4 M NaCl (+), the cells were allowed to grow for 10 min, total RNA was isolated, and the 5′ end of the ectT transcript was determined by a primer extension reaction.