Cariogenicity of Streptococcus mutans Strains with Defects in Fructan Metabolism Assessed in a Program-fed Specific-pathogen-free Rat Model
| Autor: | Howard K. Kuramitsu, William H. Bowen, Y.-Y.M. Chen, D. L. Wexler, Robert A. Burne |
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| Rok vydání: | 1996 |
| Předmět: |
Male
0301 basic medicine Glycoside Hydrolases Mutant Dental Plaque Mutagenesis (molecular biology technique) Virulence Dental Caries Biology medicine.disease_cause Dental plaque Microbiology Rats Sprague-Dawley Streptococcus mutans 03 medical and health sciences 0302 clinical medicine Fructan Bacterial Proteins medicine Animals General Dentistry Specific-pathogen-free Mutation 030206 dentistry medicine.disease biology.organism_classification Fructans Rats Specific Pathogen-Free Organisms Disease Models Animal Mutagenesis Insertional 030104 developmental biology Hexosyltransferases Biochemistry Genes Bacterial Female |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1544-0591 0022-0345 |
| DOI: | 10.1177/00220345960750080801 |
| Popis: | To define the role of dental plaque fructans and the enzymes involved in their metabolism in the initiation and progression of dental caries, we constructed otherwiseisogenic mutants of Streptococcus mutans defective in the ability to synthesize fructans, to degrade fructans, or to do both. The cariogenic potential of these organisms was evaluated in a specific-pathogen-free rat model in which the feeding patterns of the animals were controlled by means of a Konig-Hofer programed feeder. Specifically, rats were infected with wild-type S. mutans UA159 or derivatives of this strain which contained an insertionally-inactivated fructanase ( fruA) gene, fructosyltransferase ( ftf) gene, or which had both genes inactivated. The animals were fed 17 meals per day of Diet 2000 containing 56% sucrose at 70-minute intervals for five weeks, and caries experience was evaluated. Animals infected with S. mutans with a mutated fruA gene only had statistically significant decreases in sulcal caries severity. Such a decrease was not observed in previous studies with ad libitum-fed animals (Wexler et al., 1992). The manifestation of diminished virulence in the programed feeding model, but not in ad libitum-fed animals, supports the concept that the primary contribution of FruA to virulence is through the utilization of fructans storage polysaccharides. Animals infected with strains carrying the ftf mutation or simultaneous mutations in ftf and fruA did not display decreased virulence, perhaps indicating that sucrose utilization pathways may compete for substrate in vivo, or that accumulation of fructans may affect the ecology or the physicochemical characteristics of dental plaque in such a way as to reduce its cariogenic potential. The results of this study also emphasize that the contribution of a particular virulence determinant to the caries process may be highly dependent on the experimental design, feeding regimen and diet, and the presence or absence of other enzymatic activities. |
| Databáze: | OpenAIRE |
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