English: Round bodies generated in vitro rapidly elongate into spirochetes. Spirochetes were transformed into round bodies by culturing either WT-gfp or ΔrpoS-gfp isolates in RPMI for 4 days. The video is arranged into two segments depicting the rapid transformation of WT-gfp or ΔrpoS-gfp round bodies into normal spirochetes after the addition of BSK-II (see the upper left hand corner for the time stamp).