NAD+ pool depletion as a signal for the Rex regulon involved in Streptococcus agalactiae virulence
Fig 5
Galactose increases rex expression and decreases the NAD+ pool.
WT cells containing a rex promoter-lac fusion on plasmid (Prex-lac plasmid) were grown in M17 supplemented with 0.5%glucose (A) or 0.5% galactose (B). When static cultures reached OD600 = 0.5 (indicated by an arrow), they were shifted to aerated condition and grown up to stationary phase. β-galactosidase activities (β-gal.) are expressed in Miller units (M. U.). Data are representative of at least three experiments. Mean values and standard deviations are shown. (C) NAD(H) pool determination. Cells were grown in the presence of glucose or galactose (0.5%) and collected at OD600 = 0.5 (T0) and 1 hour after the static/aerobiosis shift (T1h). Data are the mean of three independent experiments and standard deviations are shown.