HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Benchabane, H. Articles by Frenette, M. Search for Related Content PubMed PubMed Citation Articles by Benchabane, H. Articles by Frenette, M.

Inactivation of the Streptococcus mutans fxpC Gene Confers Resistance to Xylitol, a Caries-preventive Natural Carbohydrate Sweetener

¹ Groupe de Recherche en Écologie Buccale, Département de Biochimie et Microbiologie (Sciences) and Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada, G1K 7P4; and
² Samuel Lunenfeld Research Institute, Mount Sinaï Hospital, 600 University Avenue, Toronto, Ontario, Canada, M5G 1X5;

*corresponding author, michel.frenette{at}greb.ulaval.ca

Xylitol is transported by Streptococcus mutans via a constitutive phosphoenolpyruvate:fructose phosphotransferase system (PTS) composed of a IIABC protein. Spontaneous xylitol-resistant strains are depleted in constitutive fructose-PTS activity, exhibit additional phenotypes, and are associated with the caries-preventive properties of xylitol. Polymerase chain-reactions and chromosome walking were used to clone the fxp operon that codes for the constitutive fructose/xylitol-PTS. The operon contained three open reading frames: fxpA, which coded for a putative regulatory protein of the deoxyribose repressor (DeoR) family, fxpB, which coded for a 1-phosphofructokinase, and fxpC, which coded for a IIABC protein of the fructose-PTS family. Northern blot analysis revealed that these genes were co-transcribed into a 4.4-kb mRNA even in the absence of fructose. Inactivation of the fxpC gene conferred resistance to xylitol, confirming its function. The fxp operon is also present in the genomes of other xylitol-sensitive streptococci, which could explain their sensitivity to xylitol.

KEY WORDS: oral streptococci • dental caries • caries prevention.

This article has been cited by other articles:

				C. Y. Loo, K. Mitrakul, I. B. Voss, C. V. Hughes, and N. Ganeshkumar Involvement of an Inducible Fructose Phosphotransferase Operon in Streptococcus gordonii Biofilm Formation J. Bacteriol., November 1, 2003; 185(21): 6241 - 6254. [Abstract] [Full Text] [PDF]