FIG. 1.

Nuc production in the NZ9000 and htrA-NZ9000 strains. Protein extracts of induced exponential-phase cultures (1 ng of nisin per ml) of the L. lactis NZ9000(pSEC:Nuc) and htrA-NZ9000(pSEC:Nuc) strains were prepared from cell (lanes C) and supernatant (lanes S) fractions and were analyzed by Western blotting by using anti-Nuc antiserum. The migration positions of precursor forms (prec) and mature forms of both NucA (A) and NucB (B) are indicated by arrows. Commercial S. aureus NucA (25 ng) was used as the standard (lane Std Nuc), and molecular masses are indicated on the left.