S. typhimurium 14028 wt, hfq and smpB were harvested from log phase LB (LBlog); (2), stationary phase LB (LBstat); (3) 4h MgM medium pH 5.0 after resuspension of LB stat culture (MgMshock); and (4) log phase MgM medium pH5.0 after 100fold dilution of an LB stat culture (MgMDil). Total RNA was extracted, cDNA labeled and hybridized to a non-redundant Salmonella whole genome PCR product ORF array.
Overall design: S. typhimurium 14028 cells were harvested, on three separate days, (1), after growth at 30°C to log phase in LB (LBlog); (2), after growth at 30°C to stationary phase in LB (LBstat); (3) after transfer of a stationary phase culture grown in LB into magnesium-deficient MgM medium [100 mM Tris-Cl, 5 mM KCl, 7.5 mM (NH4)2SO4, 0.5 mM K2SO4, 1 mM KH2PO4, 0.2% glycerol, 0.1% Casamino acids, 8uM MgCl2] pH 5.0 and growth for four more hours at 30°C (MgMshock); (4) after 100fold dilution of a stationary phase culture grown in LB into magnesium-deficient MgM medium pH5.0 and growth at 30°C to log phase (MgMDil). This procedure was performed on (A), wild type [WT] cells; (B), cells of an hfq- (STM4361) knockout mutant; and (C), cells of an smpB- (STM2688) knockout mutant, resulting in 36 samples total. Total RNA was extracted, cDNA labeled with Cy5-dCTP and hybridized versus Cy3-labeled 14028 gDNA to a non-redundant Salmonella whole genome PCR product ORF array.
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