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. Author manuscript; available in PMC: 2013 Jul 15.
Published in final edited form as: Nature. 2012 Jun 13;486(7402):271–275. doi: 10.1038/nature11090

Figure 1. Mild acid pH promotes transcription of the mgtC coding region in a Salmonella strain lacking the extracytoplasmic pH sensor PhoQ.

Figure 1

Relative mRNA levels of the coding regions of the mgtC (a), mgtB (b) and mgtA (c) genes produced by a Salmonella phoP* phoQ strain (EG10232) or derivatives with conserved A 44-46 nucleotides in the mgtCBR leader substituted by Ts (EL486). Bacteria were grown in N-minimal media with 500 μM Mg2+ at pH 7.7 for 1 h and then for an additional 1 h in the same media at pH 5.1 in the absence or presence of 0.5 μM of the protonophore carbonyl cyanide 3-chlorophenylhydrazone (CCCP). mRNA levels of target genes were normalized to that of 16S ribosomal RNA rrs gene. Shown are the mean and SD from two independent experiments. d, Intracellular ATP levels and pH of Salmonella (EG10232) grown in media with pH 7.7 and one hour after being switched to media with pH 5.1 to an OD600: 0.453. Values are in pmol of ATP per ml of cells per OD600. Shown are the mean and SD from two independent measurements.