FIG. 3.

Hydroxyectoine uptake mediated by the osmoregulated TeaABC transporter. Cells of H. elongata KB1 (ΔectA) and strain AFE35 (ΔectA teaC::Tn1732) were grown in saline minimal medium (MM63 with 170 mM NaCl). Hydroxyectoine (1 mM) was added to the medium 30 min prior to osmotic upshock. During exponential growth, KB1 and AFE35 were exposed to osmotic stress by increasing the salt concentration to 680 mM NaCl (↓). The uptake of hydroxyectoine was monitored for 60 min by analyzing the cytoplasm of KB1 and AFE by HPLC with a UV detector. At minimum, all experiments were carried out three times. Symbols: •, KB1; ▾, AFE35; ○, KB1 treated with chloramphenicol (200 μg ml⁻¹)10 min before the cells were subjected to osmotic upshock at time zero.