Results

Secretion system

In order to evaluate the secretion system, we combined our products and signal peptides (SP1,SP2 and SP3). We de novo synthesized the following peptide genes: signal peptide 1(SP1)-CPP-Flag; signal peptide 2(SP2)-CPP-Flag; signal peptide 3(SP3)-CPP-Flag; SP1-GLP-1. By linking these peptide genes with constitutively-expressed promoter and ribosome-binding site, we use either Escherichia coli K12 DH5α or Escherichia coli BL-21 strain to express them. Later, we used several methods to identify the target peptides in the extracellular fluid, the outer environment. Those methods include the dot-immunoblotting, ELISA and Western blotting. Those methods’ detail description are as below and the results are being discussed in detail.

Dot immunoblotting

Western blotting

ELISA