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Fig. 4 | Microbial Cell Factories

Fig. 4

From: Development of inducer-free expression plasmids based on IPTG-inducible promoters for Bacillus subtilis

Fig. 4

Influence of the spacer lengths between lacO1 and lacO3 on the β-galactosidase activity. The plasmids with different spacer lengths pHT1655 (143 bp), pHT2071 (280 bp), pHT1660 (548 bp) and pHT1653 (787 bp) carrying Pgrac01 (a) and pHT100 (inducible), pHT1656 (88 bp), pHT2079 (225 bp), pHT1674 (493 bp), pHT1654 (732 bp) harbouring Pgrac100 (b) were constructed. The deleted DNA region of lacI gene in the plasmids with Pgrac01 are identical to those with Pgrac100. The plasmids were transformed separately into B. subtilis 1012, and all strains were cultivated to an OD of 0.8. Then, the cultures were subdivided into two subcultures where IPTG was added at 1 mM to one of them. The BgaB activities were measured at time points 0 (immediately before addition of IPTG) and 2 and 4 h later

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