FIG. 3.

A. hydrophila SSU cells protected plasmin from its physiological inhibitor α₂AP. Human plasmin (0.25 μg) was incubated with or without 4 × 10⁸ CFU of log-phase-grown, PBS-washed A. hydrophila SSU cells for 30 to 60 min at room temperature prior to the addition of 0.45 mM S-2251 and of α₂AP in increasing concentrations (1, 8, and 16 μg). Plasmin activity was measured after 1 h of incubation at 37°C. The groups of reaction mixtures that either lacked α₂AP (control A) or contained both the bacterial cells and α₂AP (control B) were used as controls. The asterisk denotes statistically significant differences (P < 0.05) between the two groups (indicated by the horizontal lines) using a Student's t test.