FIG 2.
The ΔrelA mutant grows exclusively as single cells. (A) Representative images of wt (BJH001), ΔrelA (BQA009), ΔrelA PrelA-relA (BQA068), ΔsigD (BQA022), and Pspac-relAD264G (EUB004) cells grown to mid-log phase in CH medium. For EUB004, cells grown in the presence (+RelAD264G) and absence (−RelAD264G) of 1 mM IPTG for 120 min are shown. The membranes were stained with TMA. (B) Frequencies of chained (three or more cells linked) and unchained (single and doublet) cells across a population. The cells in images from at least three independent cultures were counted, and no fewer than 1,500 cells were quantitated for each strain represented in the graph. (C) Representative images of ΔrelA ΔsigD (BQA059) and ΔrelA Phy-sigD ΔsigD (BQA083) cells grown to exponential phase in CH medium. The membranes were stained with TMA.