Difference between revisions of "Part:BBa K1628201"

Revision as of 07:37, 18 September 2015

PlacI+lacI

Promoter PlacI is a promoter of lactose operon and LacI is a repressor of lactose operon regulating promoter PlacI. PlacI is the native promoter of LacI. PlacI and LacI together with promoter Pxyl (BBa_K1628002), promoter Pgrac (BBa_K1628202) and repressor XylR (BBa_K1628203) formed a metabolic toggle switch. We used this device to regulate the expression of odhAB genes in Bacillus amyloliquefaciens NK-1 (showed in Figure 1).

We transformed the plasmids pHT01-xylR and pCB-Pxyl into the NK-1 strain, to verify the activity of metabolic toggle switch (see it on our wiki). Fresh colonies of Bacillus amyloliquefaciens strains (NK-1 strain containing plasmids pHT01-xylR and pCB-Pxyl and the control NK-1 strain containing plasmids pHT01 and pCB-Pxyl) were first cultured overnight in test tubes containing 5 mL LB liquid and then inoculated into 100 mL fresh fermentation medium. We added 1mM IPTG into the medium after 12h of cultivation. The β-galactosidase activity were measured at 12h, 18h, 24h, 30h, 36h, 42h to test the effect of metabolic toggle switch on the expression of bgaB.

As shown in Figure 2, β-galactosidase enzyme activity dropped considerably after 30 hours of fermentation. The inhibited expression of bgsB in experiment group (NPP+IPTG) indicated that the metabolic toggle switch we constructed is functional in B. amyloliquefaciens NK-1 strain.

Sequence and Features