title: Effects of biosurfactant produced by Lactobacillus casei on gtfB, gtfC, and ftf gene expression level in S. mutans by real-time RT-PCR.
abstract: BACKGROUND
  The Streptococci are the pioneer strains in plaque formation and Streptococcus mutans are the main etiological agent of dental plaque and caries. In general, biofilm formation is a step-wise process, which begins by adhesion of planktonic cells to the surfaces. Evidences show that expression of glucosyltransferase B and C (gtfB and gtfC) and fructosyltransferase (ftf) genes play critical role in initial adhesion of S. mutans to the tooth surface which results in formation of dental plaques and consequently caries and other periodontal disease.
  
  
  METHODS
  The aim of this study was to determine the effect of biosurfactants produced by a probiotic strain; Lactobacillus casei (ATCC39392) on gene expression profile of gftB/C and tft of S. mutans (ATCC35668) using quantitative real-time PCR.
  
  
  RESULTS
  The application of the prepared biosurfactant caused dramatic down regulation of all the three genes under study. The reduction in gene expression was statistically highly significant (for gtfB, P > 0.0002; for gtfC, P > 0.0063, and for ftf, P > 0.0057).
  
  
  CONCLUSIONS
  Considerable downregulation of all three genes in the presence of the prepared biosurfactant comparing to untreated controls is indicative of successful inhibition of influential genes in bacterial adhesion phenomena. In view of the importance of glucosyltransferase gene products for S.mutans attachment to the tooth surface which is the initial important step in biofilm production and dental caries, further research in this field may lead to an applicable alternative for successful with least adverse side effects in dental caries prevention.
authors.affiliation: Department of Dental Prosthetics, School 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
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
keywords: Biosurfactants; Lactobacillus casei; oral streptococci; probiotics