Fig. 7
Promoter exchange of ftsZ and growth of the resulting strains. a Strains with FtsR-independent ftsZ expression were constructed using a DNA fragment with a terminator sequence and the gluconate-inducible gntK promoter, which was inserted between the native ftsZ promoter and the ftsZ start codon in the chromosomes of MB001 and the MB001ΔftsR mutant. b-d Effect of different gluconate concentrations on cell morphology (b) and growth (c, d) of the promoter exchange strains MB001::PgntK-ftsZ and MB001ΔftsR::PgntK-ftsZ. The two strains were first pre-cultivated in BHI medium supplemented with 0.1% (w/v) gluconate to induce ftsZ expression by PgntK. The second pre-cultivation was performed in CGXII medium with 2% (w/v) glucose supplemented with the indicated gluconate concentrations. The main cultures were then performed in media having the same composition as the ones for the second pre-cultivation. b Microscopic pictures of cells from the stationary phase. The scale bar represents 5 μm. c, d The growth experiments show mean values and standard deviations of three biological replicates