title: Effects of Lactobacillus reuteri-derived biosurfactant on the gene expression profile of essential adhesion genes (gtfB, gtfC and ftf) of Streptococcus mutans.
abstract: BACKGROUND
  Streptococci are the main causative agents in plaque formation and mutans streptococci are the principle etiological agent of dental plaque and caries. The process of biofilm formation is a step-wise process, starting with adhesion of planktonic cells to the surfaces. It is now a well known fact that expression of glucosyltransferases (gtfs) and fructosyltransferase (ftf) genes play a critical role in the initial adhesion of Streptococcus mutans to the tooth surface, which results in the formation of dental plaques and consequently caries and other periodontal diseases.
  
  
  METHODS
  In the present study, we have determined the effect of biosurfactants purified from Lactobacillus reuteri (DSM20016) culture on gene expression profile of gftB/C and fft of S. mutans (ATCC35668) using quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  The application of biosurfactant caused considerable down-regulation of the expression of all three genes under study. The reduction in gene expression was statistically very significant (P > 0.0001 for all three genes).
  
  
  CONCLUSIONS
  Inhibition of these genes by the extracted L. reuteri biosurfactant shows the emergence of a powerful alternative to the presently practicing alternatives. In view of the importance of these gene products for S. mutans attachment to the tooth surface, which is the initial important step in biofilm production and dental caries, we believe that the biosurfactant prepared in this study could be considered as a step ahead in dental caries prevention.
authors.affiliation: Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Rasoul
authors.initials: R
authors.lastname: Salehi
authors.affiliation: Department of Dental Prosthetics, Faculty of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Omid
authors.initials: O
authors.lastname: Savabi
authors.affiliation: Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Kazemi
authors.affiliation: Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Kamali
authors.affiliation: Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Salehi
authors.affiliation: Department of Parasitology and Mycology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Gilda
authors.initials: G
authors.lastname: Eslami
authors.affiliation: Department of Basic Medical Sciences, Khorasgan Branch, Islamic Azad University, Isfahan, Iran.
authors.forename: Arezoo
authors.initials: A
authors.lastname: Tahmourespour
keywords: Biosurfactants; Lactobacillus reuteri; oral streptococci; probiotics