Streptococcus mutans is the leading cause of dental caries worldwide by accumulating a glycogen-like internal polysaccharide (IPS) that contributes to cariogenicity when sugars are in excess. Sodium monofluorophosphate (MFP) is an active anticariogenic compound in toothpastes. Herein, we show that MFP inhibits (with an I0.5 of 1.5 mM) the S. mutans ADP-glucose pyrophosphorylase (EC 2.7.7.27), w...

INTRODUCTION Genotypic analyses of Streptococcus mutans using fingerprinting methods depend on a few genetic loci being different but do not reveal the underlying genome-wide differences between strains. METHODS We used comparative genomic hybridization (CGH) with 70-mer oligonucleotide microarrays containing open reading frames (ORFs) from S. mutans strain UA159 to examine the genetic divers...

Streptococcus mutans (S. mutans) is the major clinical pathogen responsible for dental caries. Its acid tolerance has been identified as a significant virulence factor for its survival and cariogenicity in acidic conditions. Small RNAs (sRNAs) are recognized as key regulators of virulence and stress adaptation. Here, we constructed three libraries of sRNAs with small size exposed to acidic cond...

Fermented beverage of plant extract was prepared from about fifty kinds of fruits and vegetables. Natural fermentation was conducted by lactic acid bacteria (Leuconostoc spp.) and yeast (Zygosaccharomyces spp. and Pichia spp.). Fourteen kinds of oligosaccharides have been isolated from this beverage; their structures were confirmed by methylation analysis, MALDI-TOF-MS and NMR measurements. In ...

The oral cavity in healthy subjects has a well-balanced microbiota that consists of more than 700 species. However, a disturbance of this balance, with an increase of harmful microbes and a decrease of beneficial microbes, causes oral disorders such as periodontal disease or dental caries. Nowadays, probiotics are expected to confer oral health benefits by modulating the oral microbiota. This s...

Streptococcus sanguinis, a normal inhabitant of the human oral cavity, has low cariogenicity, though colonization on tooth surfaces by this bacterium initiates aggregation by other oral bacteria and maturation of dental plaque. Additionally, S. sanguinis is frequently isolated from infective endocarditis patients. We investigated the functions of sortase A (SrtA), which cleaves LPXTG-containing...

Dental caries results from prolonged plaque acidification that leads to the establishment of a cariogenic microflora and demineralization of the tooth. Urease enzymes of oral bacteria hydrolyze urea to ammonia, which can neutralize plaque acids. To begin to examine the relationship between plaque ureolytic activity and the incidence of dental caries, recombinant, ureolytic strains of Streptococ...

Streptococcus mutans GS-5 and IB1600 adapted to growth in acidic environments in continuous culture at slow (generation time = 8.3 h) or fast (generation time = 2.4 h) rates of growth in complex medium with a restricted glucose supply. The extent of adaptation was indicated by changes in minimum pH values attained by harvested cells suspended in dense suspensions with excess glucose and by incr...

The proton-translocating, membrane ATPases of oral streptococci have been implicated in cytoplasmic pH regulation, acidurance, and cariogenicity. Membranes were isolated from Streptococcus mutans GS-5 and Streptococcus sanguis NCTC 10904 following salt-induced lysis of cells treated with lysozyme and mutanolysin. The ATPase activities of these membranes were 1.8 and 1.1 units per mg membrane pr...

Glycosyltransferase (Gtf) is one of the crucial virulence factors of Streptococcus mutans, a major etiological pathogen of dental caries. All the available evidence indicates that extracellular polysaccharide, particularly glucans produced by S. mutans Gtfs, contribute to the cariogenicity of dental biofilms. Therefore, inhibition of Gtf activity and the consequential polysaccharide synthesis m...