Fig.
7. Magnesium supplementation rescues the ΔybeX phenotypes in
various growth media. (A ) The WT and ΔybeX cells were
grown overnight in LB, SOB growth media, or LB supplemented with 10 mM
MgCl2. The cells were serially diluted and spotted on LB
agar plates. The plates with antibiotics were incubated at 37°C. There
were also controls without antibiotics, denoted “No AB”, at 37°C or
42°C, as indicated in the first two sub-panels. (B ) A single
colony of WT or ΔybeX was grown overnight in the
magnesium-limited peptide-based medium (PBM). 0 µM denotes no
MgCl2 supplementation; otherwise, PBM is supplemented
with 50, 100 and 200 µM MgCl2. The cells were plated as
in panel A. (C ) WT and ΔybeX cells were grown overnight
at 37°C in MOPS minimal medium supplemented with indicated
concentrations of MgCl2 and 0.5% glucose. The outgrowth
from these stationary phase cultures was tested in 1xMOPS minimal medium
(0.5% glucose, 525 µM MgCl2) in 96-well plates at 37°C
with aeration. The growth curves summarize three independent experiments
shown as fitted logistic curves. Shaded areas represent the 95% CI-s.