Figure 1.

LetS increases the culturability of Lp in water. (A and B) CFU counts of the WT, ∆letS and the induced (ON) or uninduced (OFF) ∆letS + pletS was monitored in water at 42 °C. In panel A, ON was induced only in water, while in panel B, the ON strain was induced on agar prior to water exposure and during water exposure. Panel C and D show CFU counts of the WT, ∆letS, ON and OFF at 4 °C and 25 °C respectively. The ON strain in panels C and D was induced on agar prior to water exposure and during water exposure. Strains were suspended in water at an OD₆₀₀ of 0.02. ON was induced with 0.1 mM IPTG. DL, detection limit. An unpaired, one-tailed Student’s t-test was used to assess statistical significance versus the WT. *p < 0.05; **p < 0.005; ***p < 0.0005.