Oral bacteria may halt dental plaque
Oral health experts are suggesting that an enzyme produced by mouth bacterium inhibits dental plaque.
The finding could eventually lead to the development of toothpaste that harnesses the body's own plaque-fighting tools.
The team of scientist from Japan show that the bacterium, Streptococcus salivarius, a non-biofilm forming and otherwise harmless inhabitant of the human mouth, actually inhibits the formation of dental biofilms – or plaque.
The bacteria produces two enzymes that are responsible for this inhibition.
The research is published in the March 2011 issue of the journal Applied and Environmental.
Author, Hidenobu Senpuku, of the National Institute of Infectious Diseases in Tokyo, says of one of the enzymes: "FruA" may be useful for prevention of dental caries. The activity of the inhibitors was elevated in the presence of sucrose, and the inhibitory effects were dependent on the sucrose concentration in the biofilm formation assay medium.
‘We show that FruA, produced by S. salivarius inhibited S. mutans biofilm formation completely in the in vitro assay supplemented with sucrose.'
S. salivarius is the primary species of bacteria inhabiting the mouth, according to the report.
The authors suggest that FruA may actually regulate microbial pathogenicity in the oral cavity.
They found that a commercial FruA, produced by Aspergillus niger, was as effective as S. salivarius FruA at inhibiting S. mutans biofilm formation, despite the fact that its amino acid composition is somewhat different from that of S. salivarius.
FruA is produced not only by S. salivarius, but by other oral streptococci.
5th Apr 2011
Inhibition of Streptococcus mutans biofilm formation by Streptococcus salivarius FruA.
Department of Bacteriology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
The oral microbial flora consists of many beneficial species of bacteria that are associated with a healthy condition and control the progression of oral disease.
Cooperative interactions between oral streptococci and the pathogens play important roles in the development of dental biofilms in the oral cavity.
To determine the roles of oral streptococci in multispecies biofilm development and the effects of the streptococci in biofilm formation, the active substances inhibiting Streptococcus mutans biofilm formation were purified from Streptococcus salivarius ATCC 9759 and HT9R culture supernatants using ion exchange and gel filtration chromatography.
Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry analysis was performed, and the results were compared to databases.
The S. salivarius HT9R genome sequence was determined and used to indentify candidate proteins for inhibition. The candidates inhibiting biofilms were identified as S. salivarius fructosyltransferase (FTF) and exo-beta-d-fructosidase (FruA). The activity of the inhibitors was elevated in the presence of sucrose, and the inhibitory effects were dependent on the sucrose concentration in the biofilm formation assay medium. Purified and commercial FruA from Aspergillus niger (31.6% identity and 59.6% similarity to the amino acid sequence of FruA from S. salivarius HT9R) completely inhibited S. mutans GS-5 biofilm formation on saliva-coated polystyrene and hydroxyapatite surfaces. Inhibition was induced by decreasing polysaccharide production, which is dependent on sucrose digestion rather than fructan digestion. The data indicate that S. salivarius produces large quantities of FruA and that FruA alone may play an important role in multispecies microbial interactions for sucrose-dependent biofilm formation in the oral cavity.
- [PubMed - in process]
- PMCID: PMC3067281
- [Available on 2011/9/1]