FIG. 3.
BC202, an engineered yghB yqjA double-deletion strain. (A) Growth of BC202 (ΔyghB::Kanr ΔyqjA::Tetr) on LB agar plates at 30 and 42°C. (B) Growth of W3110 and BC202 in liquid medium at 44°C. Cell growth was monitored as described in the legend to Fig. 2. (C) Lud135 and BC202 undergo lysis during growth at 44°C. W3110A, Lud135, and BC202 were grown in LB-Tet medium containing 1 mM IPTG at 30°C to OD600s of 0.80, 0.91, and 0.76, respectively. One milliliter of each culture was added to 25 ml of LB-Tet-IPTG prewarmed to 44°C and cultures were grown with shaking for 3 hours at this temperature. Final OD600s of the 44°C-grown cultures were 1.33, 0.31, and 0.36, respectively. Cell-free medium was recovered by centrifuging the cultures and filtering supernatants through a 0.45-μm filter. β-Galactosidase activity in the medium was assayed as described previously (33). Values represent the averages of three determinations and error bars indicate standard deviations.