Plasminogen activation by <i>Streptococcus oralis</i>.

<p>(<i>A</i>) Bacterial cells from mid-logarithmic culture of <i>S. oralis</i> SV11 were incubated in human plasma (<b>○</b>) or PBS (<b>⋄</b>). Plasma without bacteria was used as a control for auto-activation (<b>□</b>). Incubation of plasma with 100 ng urokinase served as a positive control (<b>▵</b>) (B) Bacterial cells from mid-logarithmic culture of <i>Streptococcus oralis</i> SV11 were incubated in PBS (<b>⋄</b>) or PBS containing purified human plasminogen (<b>○</b>). Plasminogen without bacterial cells (<b>□</b>) served as a control for auto-activation. Incubation of human plasminogen with 100 ng urokinase served as a positive control (<b>▵</b>), demonstrating that the plasminogen could be activated. Plasminogen activation was measured using the colour reaction of plasmin-specific substrate (S-2251). The diagrams depict the absorbance of the liquid phase measured at a wavelength of 405 nm vs. time.