Expression of the mgrA gene in the different wild-type strains at the various phases of growth. (a) Northern blots were hybridized with 565 bp DNA fragments containing the coding region of the mgrA gene. A total of 10 μg RNA was loaded in each lane. Lanes 1–6, total cellular RNA from the growing cultures at OD600 0.3, 0.7, 1.1, 1.4, 1.7 and overnight (stationary) (Manna & Ray, 2007). P1 (0.56 knt) and P2 (0.75 knt) indicate the two transcripts of the mgrA locus (Ingavale et al., 2003). The region containing the 23S and 16S rRNA of the ethidium bromide-stained gel used for blotting is shown as a loading control. The third and sixth panels from the top represent the Western blot analyses for MgrA with anti-MgrA antibody in the different wild-type strains. Equivalent amounts of extracts (20 μg) from the different phases of growth (OD600 ∼0.7, early exponential; OD600 ∼1.1, exponential; OD600 ∼1.7, post-exponential) were used to detect MgrA expression. (b) Growth curves for the wild-type RN6390 and COL strains. There was no noticeable difference in growth of other strains. The OD600 of various cultures was measured in a Spectronic 20D spectrophotometer.