Affiliation:
1. Department of Microbiology, Northwestern University Medical and Dental Schools, Chicago, Illinois 60611
Abstract
The mechanism of adsorption of the
Streptococcus mutans
enzymes responsible for the synthesis of insoluble dextran-levan to the
S. mutans
cell-wall binding sites has been studied. Certain characteristics of these binding sites are presented. The adsorption of these enzymes to the cell surface occurred rapidly without the addition of a source of energy and over a pH range of 3 to 11. The adsorption was inhibited by soluble dextran, probably due to the strong affinity of the polymer to the enzyme. All other polymers and sugars studied showed little or no inhibition. The adsorption was also inhibited by antibody globulin to the
a-d
immunologically specific group antigen surface polysaccharide of
S. mutans
and by anti-dextran globulin. The inhibition by anti-
a-d
globulin is considered to be due to a restriction of access of enzyme to the binding site of the enzyme which may be located in close proximity to the group antigen. On the other hand, anti-dextran globulin appeared to directly inhibit the adsorption by covering the binding site. Dextranase destroyed the binding site and released glucose from the
S. mutans
cells. These data indicate that
S. mutans
grown in media containing glucose possesses a small amount of dextran on the cell surface, and that this dextran is, or is a part of, the binding site for enzymes which synthesize the insoluble dextran-levan polymer. Trypsin inhibited the synthesis of insoluble polysaccharide and the adherence of cells. It is not clear in this case that destruction of the binding sites occurred. These data present a partial explanation of the processes which may be concerned in the formation of dental plaque on the smooth surfaces of teeth.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
112 articles.
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