Fig. 8

Excretion of ectoine and 5-hydroxyectoine in E. coli strains lacking mechanosensitive channels. The E. coli strains FF4169 (otsA::Tn10), Frag1 (wild-type), MJF465 (mscL mscS mscK), and MJF641 (mscL mscS mscK mscM) harboring the plasmid pMP41 (ectD gene from P. stutzeri A1501) were grown in MMA that contained ampicillin, 0.4 M NaCl, and 10 mM ectoine. Plasmid-based overexpression of the ectD gene was induced by the addition of AHT to the growth medium; the cultures were subsequently grown for 24 h. Both the extracellular (a) and the intracellular (b) concentrations of ectoine (grey) and 5-hydroxyectoine (red) were determined via HPLC analysis. The values shown are the means and standard deviations of four independent cultures. The strains with defects in various mechanosensitive channel genes (MJF465, MJF641) are derivatives of Frag1. The values shown are the means and standard deviations of four independently tested cultures