FIG. 4.

Long-term survival of serovar Typhimurium in colonies of the rdar morphotype. A. RpoS (σ³⁸) activity in growing cells was monitored using the sig38H4 promoter::lux fusion. Colonies were inoculated with 10⁵ cells from an overnight culture and were grown at RT (∼22°C) for 50 days. Pictures were taken at the times indicated to record colony morphology (white) or luminescence production (lux). B. Individual rdar colonies peeled off the surface of T agar were stored for 3 to 9 months at RT in plastic wells of a 24-well plate in the absence of nutrients prior to testing survival and resistance to bleach treatment.