Modulation of glycosidase and protease activities by chemostat growth conditions in an endocarditis strain of Streptococcus sanguis.

摘要: The effects of growth conditions on the properties endocarditis-producing oral bacterium Streptococcus sanguis FSS2 were studied. This strain produces a variety proteases and glycosidases, including thrombin-like activity that is potential virulence factor for endocarditis. Cultures grown with limiting glucose or galactose in chemostats over range dilution rates pH levels, following activities measured at 7.5: thrombin-like, Hageman factor-like, N-acetyl-beta-D-galactosaminidase, beta-D-glucosidase, beta-D-galactosidase. At 6.5, specific generally decreased as rate increased from 0.05 to 0.40 h(-1). 0.1 h(-1), highest 6.5 lower approximately equal 5.5 7.5. major exception was activity, which 7.5 5-fold higher than 5.5. factor-like apparently catabolite repressible, its 3-fold cultures. changed functions thus modulated by environment. Environmental regulation consistent an less important tooth surfaces tissues.