The optimal dosage and duration of a LAc-based regimen for an area with high H. pylori resistance to amoxicillin and/or clarithromycin require more investigations.
PALZ39E is a mouse erythroleukemia (MEL) cell line stably transgenic for a GFP lac repressor fusion protein and with multiple integrations of the 15 kbp plasmid pPALZ8.8 containing 64 repeats (2.5 kbp) of the lac operator binding site (lacO), β-globin regulatory sequences and a β-galactosidase reporter gene [ 7].
To reduce basal expression, a lac operator sequence (a binding site for lac repressor) is placed downstream of the T7 promoter, constructing a T7 lac promoter [ 15].
Both vectors contain T7 RNA polymerase promoters, but pN110 also contains a lac operator (lacO) downstream of the promoter and the gene encoding the lac repressor (lacI) for tighter control of gene expression.
See Supporting Information Table 5 for all lac induction promoter sequences.
To predict the balance between costs and benefits of expression, both must be measured for a range of lac operon expression levels, but at constant lactose concentrations.
However, laccaic acid A, 3-[3- 2-acetamidoethyl -6-hydroxyphenyl]-1,2,4,7-tetrahydroxyanthraquinone-5,6-dicarboxylic acid, is usually chosen as a representative for the lac dye to describe their kinetics and thermodynamics of adsorption.
For the lac system, a large number of artificial compounds have been synthesized [ 13], that interact with the gene products in a different way than lactose.
The T7 lac promoter is a combination of the T7 bacteria phage promoter placed upstream of the lac operator (lacO) sequence, a binding site for the lac repressor.
Studier previously developed a reliable protocol for the lac operon/promoter-dependent auto-induction of genes in E. coli [ 14].
