Synthetic biological systems often require multiple, independently inducible promoters in order to control the expression levels of several genes; however, cross talk between the promoters limits this ability. Here, we demonstrate the directed evolution of AraC to construct an arabinose-inducible (P(BAD)) system that is more compatible with IPTG (isopropyl-beta-D-1-thiogalactopyranoside) induct...

Growth and media Liquid cultures were grown at 37°C with aeration in minimal A medium (Miller, 1992) with 0.2% glycerol or glucose as the carbon source or in LB Miller medium (Difco). Colonies were grown at 37°C on 1.5% agar plates made from LB Miller medium or minimal A medium with glycerol as the carbon source. Plasmids were maintained by supplementing media with 50 μg/mL of ampicillin, 15 μg...

The aim of the study was to optimize conditions for producing Salmonella Enteritidis recombinant heat shock protein 60 (rHsp60). Seven Escherichia coli host strains (Rosetta, Turner, C41, C43, Origami, BL21pLys, Rosetta pLys) were transformed by a recombinant plasmid containing Hsp60 gene from Salmonella Enteritidis, and then cultured and induced by isopropyl-beta-D-thiogalactopyranoside (IPTG)...

Alkaline phosphatase is an enzyme with widespread use in research and industry such as protein labeling, dephosphorylation of nucleic acids, and enzyme based biosensors. In the present study, alkaline phosphatase gene was inserted into the pET15b vector. The recombinant DNA was then expressed using IPTG as an inducer. The expression of this enzyme was optimized by changing expression conditions...

Induction parameters including inducer concentration, period of induction and the cell concentration at which inducer is to be added to the fermentation broth were optimized in order to increase the yield of the EcoRI restriction endonuclease isolated from recombinant E. coli. Bacterial cells harboring the plasmid pPG430 containing EcoRI endonuclease and the methylase genes under the control of...

A new non-specific nuclease from Yersinia enterocolitica subsp. palearctica (Y. NSN) was expressed in Escherichia coli (E. coli) BL 21 StarTM (DE3)plysS. Induction conditions, including isopropyl-β-D-thiogalactoside (IPTG) concentration, cell density (OD600), induction time and induction temperature, were optimized using response surface methodology. Statistical analysis of the results revealed...