title: Effect of dextranase and protease enzymes on aggregation of Streptococcus mutans: colorimetric and electron microscopic studies.
abstract: Sucrose-induced aggregation of Streptococcus mutans was ascertained by measuring the decrease in optical density of a cell suspension after 20 h incubation. The optimum sucrose concentration for the aggregation assay was 5% w/v, at an incubation temperature of 37 degrees C. Dextranase and protease enzymes were added to the suspensions to determine their effects on aggregation. Dextranase treatment decreased aggregation. Electron microscopic studies revealed a reduction in the amount of a diffuse coat which surrounded cells in the absence of the enzyme but in the presence of sucrose, and a degradative effect on fibrous extracellular material. Protease treatment of suspensions produced an increase in optical density; cell aggregates were not apparent. Electron microscopic studies revealed extensive cell damage and lysis. The success of these enzymes in decreasing aggregation would indicate a role in both caries and plaque control in vivo.
mesh_terms: D003124:Colorimetry; D003910:Dextranase / Q000494:pharmacology*; D010450:Endopeptidases / Q000494:pharmacology*; D008666:Metalloendopeptidases; D008854:Microscopy, Electron; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure
chemical_list: D003910:Dextranase; D010450:Endopeptidases; D008666:Metalloendopeptidases; C022653:auR protein, Staphylococcus aureus