The objective of this study was to develop PCR primers that are specific for Streptococcus sanguinis, Streptococcus parasanguinis, and Streptococcus gordonii. We designed the S. sanguinis-, S. parasanguinis-, and S. gordonii- specific primers, Ssa21-F3/Ssa21-R2, Spa17-F/Spa17-R, and Sgo41-F1/Sgo41-R1 respectively, based on the nucleotide sequences of the Ssa21, Spa17, and Sgo41 DNA probes that were screened using inverted dot blot hybridization (IDBH). The species-specificity of these primers was as- sessed against 43 strains of mitis group streptococci, in- cluding clinical strains of S. sanguinis, S. parasanguinis, and S. gordonii. The resulting PCR data revealed that species-specific amplicons had been obtained from all strains of the target species tested, and that none of these amp- licons occurred in any other strains from other species. These results suggest that the Ssa21-F3/Ssa21-R2, Spa17- F/Spa17-R, and Sgo41-F1/Sgo41-R1 primers may be useful in detecting S. sanguinis, S. parasanguinis, and S. gordonii at the species level, respectively.
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causative microbes for nosocomial infe- ction and has been isolated from the dental environment. The purpose of this study was to investigate the antimi- crobial activity of linalool and α‐terpineol against MRSA isolates from a Korean population. In the experiments, we determined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two compounds against 18 strains of MRSA. The data re- vealed that the MIC90/MBC90 values of linalool and α‐ terpineol against MRSA were >12.8 mg/ml and 6.4 mg/ml, respectively. These results indicate that α-terpineol has more potent antimicrobial activity against MRSA than lina- lool and may have utility as an anti‐MRSA cleansing agent for dental instruments and dental unit chairs.
TM7 is an uncultivated organism which is present in ex- tremely diverse environments. Members of the Dialister genus are difficult to culture as a result of which many of these strains remain uncultivated. It has been suggested that TM7 and Dialister bacteria may belong to a group of suspected periodontal pathogens. In our current study, the presence of the sebacteria in Korean dental plaque samples was asses- sed using PCR detection methods with specific primers for 16S ribosomal RNA genes. The experimental group inclu- ded 84 volunteers (35 males and 49 females). Plaque sam- ples were collected from 4 non-adjacent proximal sites of the molar areas of the mandible in each subject and pooled. TM7 was detectable in 56% and the Dialister genus in 27.5% of the volunteers. Both TM7 and Dialister were present in 20.3% of volunteers. We found that 36.9% of the volunte e rs we re negative for both bacteria. Further s tudi e s to evaluate the prevalence of these putative pathogenic bac- te ria in the Korean population are warranted.
Erythromycin is a macrolide antibiotic and inhibits bac- terial protein synthesis by stimulating the dissociation of the peptidyl-tRNA molecule from the ribosomes during elon- gation. The use of macrolides has increased dramatically over the last few years and has led to an increase in bac- terial resistance to these antibiotics. Bacterial resistance to erythromycin is generally conferred by the ribosome methy- lation and/or transport (efflux) protein genes. Among the identified erythromycin-resistant genes, erm(B) (erythromy- cin methylation) and mef(A) (macrolide efflux) are gene- rally detectable in erythromycin-resistant streptococcal spe- cies. The distribution of these genes in oral streptococcal iso- lates has been reported in studies from other countries but has not been previously examined in a Korean study. We here examined by PCR the presence of erm(B) and mef(A) in oral streptococci isolated from Korean dental plaques. Among the 57 erythromycin-resistant strains tested, 64.9% harbored erm(B) whereas 40.4% were positive for mef(A). Eleven isolates had both the erm(B) and mef(A) genes. Twenty six isolates had only erm(B) and 12 isolates had only mef(A). Eight of the 57 strains examined were negative for both genes.
This study examined the anti-osteoclastogenic effects of baicalin on receptor activator of NF-kB ligand (RANKL)- induced RAW264.7 cells. Baicalin is a flavonoid that is produced by Scutellaria baicalensis and is known to have multiple biological properties, including antibacterial, anti- inflammatory and analgesic effects. The effects of baicalin on osteoclasts were examined by measuring 1) cell via- bility; 2) the formation of tartrate-resistant acid phosphatase (TRAP) (+) multinucleated cells; 3) RANK/RANKL signa- ling pathways and 4) mRNA levels of osteoclast-associated genes. Baicalin inhibited the formation of RANKL-stimu- lated TRAP (+) multinucleated cells and also suppressed the RANKL-stimulated activation of p-38, ERK, cSrc and AKT signaling. Baicalin also inhibited the RANKL-stimu- lated degradation of IĸB in RAW264.7 cells. In addition, the RANKL-stimulated induction of NFATc1 transcription factors was found to be abrogated by this flavonoid. Baica- lin was further found to decrease the mRNA expression of osteoclast-associated genes, including carbonic anhydrase II, TRAP and cathepsin K in the RAW264.7 cells. Our data thus demonstrate that baicalin inhibits osteoclastogenesis by inhibiting the RANKL-induced activation of signaling molecules and transcription factors in osteoclast precursors.
Leptin is one of the adipocytokines produced from adi- pose tissue but its functions in periodontal tissue have not previously been investigated. In our current study, we exa- mined the effects of leptin on the expression of interleukin (IL)-6 and IL-8 in periodontal ligament (PDL) cells and gingival fibroblasts. Leptin receptor expression was evalua- ted by RT-PCR and the production of cytokines was mea- sured by ELISA. The phosphorylation of Akt and Erk1/2 was assessed by western blotting. mRNA of long and short form leptin receptors were detected in both PDL cells and gingival fibroblasts. Leptin was found to increase the pro- duction of IL-6 and IL-8 in both of these cell types, an effect which was not blocked by polymyxin B, an inhibitor of lipopolysaccharide (LPS). Leptin did not alter the pro- duction of IL-6 and IL-8 induced by LPS in PDL cells but increased Akt and Erk1/2 phosphorylation in these cells. These results suggest that leptin acts as an inducer of IL-6 and IL-8 in PDL cells and gingival fibroblasts.
There are estimated to be about 700 species of bacteria in the oral cavity. Based on epidemiological investigations, some of these strains have been proposed as the pathogens responsible for oral diseases such as dental caries, gingivitis and periodontitis. Since electrolyzed hydrogen-rich water has been shown to have beneficial effects on human im- munity, its use has increased. In our study, the antibacterial activity of hydrogen-rich water for oralagainst bacteria asso- ciated with oral disease was evaluated. The bacterial strains Streptococcus mutans, Fusobacterium nucleatum, Porphy- romonas gingivalis and Tannerella forsythia were cultured in specific growth medium. S. mutans, F. nucleatum and P. gingivalis were soaked to thein both hydrogen water and tap water for 30 sec and then inoculated onto mitis-sali- varius agar and brain heart infusion agar including supple- mented withvitamin K and hemin, respectively. The num- bers of bacterial colonies were then measured after cultiva- tion for 48 hours. In the case of T. forsythia, which does not grow well on agar plates, inoculations into modified new oral spirochete (NOS) broth were performed and growth curve analysis was undertaken every day with a spectrophotometer. Hydrogen water showed antibacterial activity against all four bacterial strains in comparison with tap-water. We conclude from this that hydrogen water may have a positive impact on oral hygiene by helping to remove cariogenic bacteria and periodontopathogens.