Western hybridization using the NsoA1 leader antibody to detect pre-peptide production in UKLc10. Comparison of L. lactis TCA-precipitated culture supernatant extracts (lanes 1–5) or cell extracts (lanes 6–11) from UKLc10 (lanes 1, 2, 4–8, 10 and 11) or MG1614 (lanes 3 and 9) containing plasmids pnsoAΔA (lanes 1 and 11), pnsoA (lanes 2, 6 and 10), pnsoAΔA, pTGnsoA3-nsoA4 (lanes 3 and 9), pIL253 (lanes 4 and 8) and pnsoA pTGnsoA3-nsoA4 (lanes 5 and 7). Samples were induced with nisin for 3 h, except for lane 6 (2 h). M, marker.