Characterization and expression of the ial gene and in vivo activity of the IAL in P. chrysogenum. (A) Southern blotting carried out with genomic DNA extracted from the npe-10-AB·C and Wis54-1255 strains and digested with Hind III. The ial gene was used as probe. (B) HPLC analysis confirming the production of IPN by the npe10-AB·C strain. (C) Chromatogram showing the lack of 6-APA production in the npe10-AB·C strain. (D) Chromatogram showing the lack of benzylpenicillin production in the npe10-AB·C strain. (E) Northern blot analysis of the ial gene expression in npe-10-AB·C and Wis54-1255 strains. Expression of the β-actin gene was used as positive control.