FIG 2.

Serralysin (PrtS) is required for the majority of secreted protease activity and cytotoxic power of supernatants from a keratitis isolate of S. marcescens. (A) Secreted protease activity from bacterial supernatants measured by azocasein (n = 7). (B) Cytotoxicity of secreted supernatants to HCLE cells (n = 6). Vector = pMQ125, pprtS = pMQ356. Mock-treated cells had 0% cytotoxicity, and detergent-treated cells had 100% cytotoxicity. Means and standard deviations are shown. The asterisk indicates a difference from K904 plus vector by ANOVA with Tukey's posttest.