Fig. 6
The effect of adding selected saccharides to the culture medium on GFPuv-coding gene expression in the Tabor-Studier system. The cultures were grown at 37 °C in LB medium containing tryptone (a non-inducing animal-based component). When the culture reached OD600  = 0.6–0.8, one of the tested saccharides was added to a final concentration of 1 mM: A negative control culture, no saccharide added; B positive control culture, IPTG added; C glucose; D galactose; E saccharose; F raffinose; and G stachyose. The culture samples were taken at 1-h intervals starting from the moment the culture reached OD600  = 0.6–0.8 and were subjected to spectrophotometric and 10% SDS-PAGE analysis. (Lane M) Pierce™ Unstained Protein MW Marker (Thermo Scientific); (Lane K) purified recombinant GFPuv protein; (Lane T0) E. coli BL21(DE3) [pET21d(+)-gfpuv] cells at OD600 = 0.6–0.8; (Lane T1) cells 1 h after the culture reached OD600 = 0.6–0.8; (Lane T2) 2 h; (Lane T3) 3 h; (Lane T4) 4 h; (Lane T5) 5 h; (Lane T6) 6 h; and (Lane T7) 7 h. The arrows indicate the position (26.8 kDa) at which GFPuv migrates in the gel. The red arrows indicate GFPuv in the samples containing the expressed gfpuv gene