Effects of variations in pH and hypothiocyanite concentrations on S. mutans glucose metabolism.
Hypothiocyanous acid (HOSCN) and hypothiocyanite (OSCN-) were generated by the antibody-independent salivary peroxidase (SP) system. The metabolism of Streptococcus mutans NCTC 10449 was examined by uniformly labeled glucose incorporation studies. We found that the SP-system causes a pH-dependent inhibition of 14C-labeled glucose uptake, and that the effects of HOSCN/OSCN- are bacteriostatic. The results also showed that, at low pH, bacteria required more time to recover fully from HOSCN/OSCN- inhibition. When control experiments were performed in the absence of HOSCN/OSCN-, but the pH was varied, we found a positive correlation between pH and the rate of 14C-glucose incorporation. The results also showed that pH did not affect the maximum incorporation of 14C-glucose, demonstrating that S. mutans can adapt to pH changes in the environment. Based on the data obtained, we postulate that the antibody-independent SP system plays an important role in the regulation of the metabolism of oral streptococci.
D005947:Glucose / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000378:metabolism; D009195:Peroxidase; D010544:Peroxidases / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000378:metabolism; D013295:Streptococcus mutans / Q000187:drug effects / Q000378:metabolism*; D013861:Thiocyanates / Q000494:pharmacology*
D007527:Isoenzymes; D012471:Salivary Proteins and Peptides; D013861:Thiocyanates; C014607:hypothiocyanite ion; D006861:Hydrogen Peroxide; D010544:Peroxidases; D009195:Peroxidase; D005947:Glucose