FIG. 1.

Secretion of recombinant insulinotropic proteins by E. coli Nissle. Nissle was engineered to secrete either GLP-1 under the control of the fliC promoter or PDX-1-CPP under the control of a glucose-responsive element. Western blots for secreted proteins GLP-1 (top blot) and PDX-1-CPP (bottom blot) are shown. Cells were grown for 6 to 8 h, normalized to an optical density at 600 nm of 1, and centrifuged. The pellets were lysed, and the amount of each protein was determined (fraction “C”). The supernatant was preserved and similarly analyzed (fraction “M”). For cells expressing PDX-1-CPP, a comparison was made between cells grown in medium containing glucose (0.4%) or glycerol (0.4%). Cells expressing the empty plasmid (20) were used as a negative control.