Our long-term objective is to understand the number, control and interactions of all gene products involved in the various stages leading to Steptococcus mutans pathogenicity including sucrose-independent and dependent adherence, aggregation, complex carbohydrate biosynthesis, and carbohydrate metabolism and acid production. Our current efforts are directed at those gene products which influence those processes which occur on the S. mutans cell surface. Specifically, we will: 1) further characterize and establish the mechanism by which a water-soluble glucan produced by an adherence-defective dextranase-negative S. mutans mutant inhibits plaque formation and cariogenicity of wild-type S. mutans strains, 2) further characterize the roles of the SpaA protein in S. mutans virulence and elucidate its relationship to dextranase and glucan-binding, 3) isolate and characterize mutants that are defective in being agglutinated by the agglutinin from Persea americana, 4) study the function and regulation of the gtfA gene product using insertional inactivation of and lacZ fusions with the gtfA gene cloned on a shuttle plasmid vector, 5) construct a Tn5 or Tn903 derivative in which kanamycin-resistance and transposition will be under the control of a promoter functioning in S. mutans and in Escherichia coli, 6) isolate new mutants of S. mutans with genetic defects in the synthesis and placement of known protein products by (i) introducing defective S. mutans genes that had been previously cloned into and characterized in E. coli strains and (ii) selecting mutants for the absence of cell surface proteins by using antibodies against specific S. mutans gene products expressed by E. coli recombinant clones, 7) characterize both existing and newly isolated mutants for (i) presence of cell surface protein products using immunological techniques and antisera raised against such proteins expressed by E. coli recombinants, (ii) ability to adhere, aggregate and produce acid, (iii) presence of enzymes such as glucosyltransferase, fructosyltransferase, dextranase and invertase and (iv) ability to complement each other for adherence, aggregation and plaque formation during mixed cultivation, and 8) evaluate the virulence of mutants alone and in combination in gnotobiotic rats.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
2R01DE006801-03
Application #
3220267
Study Section
Oral Biology and Medicine Study Section (OBM)
Project Start
1983-08-01
Project End
1990-07-31
Budget Start
1985-08-01
Budget End
1986-07-31
Support Year
3
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Washington University
Department
Type
Schools of Arts and Sciences
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Hudson, M C; Curtiss 3rd, R (1990) Regulation of expression of Streptococcus mutans genes important to virulence. Infect Immun 58:464-70
Barletta, R G; Curtiss 3rd, R (1989) Impairment of melibiose utilization in Streptococcus mutans serotype c gtfA mutants. Infect Immun 57:992-5
Barletta, R G; Michalek, S M; Curtiss 3rd, R (1988) Analysis of the virulence of Streptococcus mutans serotype c gtfA mutants in the rat model system. Infect Immun 56:322-30
Curtiss 3rd, R; Pearce, C; Pollack, J et al. (1987) Isolation and characterization of mutants of Streptococcus mutans using selective removal of wild-type cells by agglutination with an agglutinin from Persea americana. Acta Microbiol Pol 36:3-15
Switalski, L M; Murchison, H; Timpl, R et al. (1987) Binding of laminin to oral and endocarditis strains of viridans streptococci. J Bacteriol 169:1095-101
Murchison, H H; Barrett, J F; Cardineau, G A et al. (1986) Transformation of Streptococcus mutans with chromosomal and shuttle plasmid (pYA629) DNAs. Infect Immun 54:273-82
Murchison, H; Larrimore, S; Curtiss 3rd, R (1985) In vitro inhibition of adherence of Streptococcus mutans strains by nonadherent mutants of S. mutans 6715. Infect Immun 50:826-32