FIG. 7.

Proteinase production by BEAS cells and P. aeruginosa. Proteinase activities present in culture medium containing of 10⁹, 10⁷, or 10⁵ CFU of PA103/ml (A and D), PAO1 (B, D, and E), and 6294 (C, D, and E) with (+) and without (−) BEAS cells were visualized by gelatin zymography. Samples containing 1.5 μl (∗), 15 μl (∗∗), and 4 μl (∗∗∗) of medium were electrophoresed on SDS–8% polyacrylamide gels containing 0.2% gelatin. Following electrophoresis, the gels were incubated overnight in cleavage buffer, and the cleaved bands were visualized by negative staining with Coomassie brilliant blue. LasB, P. aeruginosa-encoded elastase; AprA, P. aeruginosa-encoded alkaline protease; GelA, gelatinase A (MMP2 encoded by BEAS cells). (F) Elastase standard.