[Identification of main chemical constituents of diterpene lactone effective fraction of Andrographis panniculata by HPLC-DAD/ESI-MS and their preliminary pharmacodynamics research].

Objective: To establish an HPLC-DAD/ESI-MS method for quickly identifying chemical constituents in diterpene lactone effective fraction of Andrographis panniculata and to study its pharmacodynamics.

Method: The separation was performed on an Agilent SB-C18 column (2.1 mm x 150 mm, 5 μm) with a mobile phase of acetonitrile (A) and water (B).

Cloning, expression and characterization of antimicrobial porcine β defensin 1 in Escherichia coli.

Porcine β defensin 1 (pBD1) is a cationic antimicrobial peptide with three pairs of disulfide bonds. When expressed in insect cells, two polypeptides of different length (pBD1(38) and pBD1(42)) accumulated, which differed by N-terminal truncation. However, only pBD1(42) was found in pigs.

Molecular cloning, expression and characterization of the porcine β defensin 2 in E. coli.

Porcine β defensin 2(pBD2)is a cationic 37-amino acid antimicrobial peptide with disulfide bonds. Synthetic pBD2 had broad antimicrobial activity against pathogenic bacteria, and thus pBD2 could be a good candidate as a bactericidal agent for pigs. This study reported the successful recombinant expression of pBD2 in Escherichia coli and analysis of its antimicrobial activity, its hemolytic activity, salt-tolerance and thermal stability as well.