start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue=1 article-no= start-page=27047 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250725 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Prevalence of Streptococcus mutans harboring the cnm gene encoding cell surface protein Cnm in Japanese children en-subtitle= kn-subtitle= en-abstract= kn-abstract=Dental caries is a highly prevalent infectious disease primarily caused by the pathogenic bacterium Streptococcus mutans, which has also been associated with systemic disease. A 120-kDa collagen-binding protein (Cnm) produced by S. mutans contributes to cardiovascular disease pathogenicity. Few studies have addressed the current prevalence of S. mutans and the cnm gene in Japanese children or examined caries pathology in relation to cnm presence. Here, we investigated the prevalence of S. mutans and the distribution of cnm-positive S. mutans among 490 children who visited two university hospitals in Japan. The caries experience index (dmft/DMFT) was calculated, and the collagen-binding ability of cnm-positive S. mutans strains was assessed. S. mutans was isolated from the oral cavities of 158 patients (36.8%); 10.1% (16/158) harbored cnm-positive S. mutans. When caries experience indices were compared across dentitions, patients harboring cnm-positive strains had significantly higher dmft/DMFT scores than those with cnm-negative strains (P? Streptococcus mutans, a biofilm-forming bacterium, possesses several transporters that function as import/export molecules. Among them, the PII protein family is composed of members that regulate glutamine synthesis in bacterial species.
Objective
In this study, we characterized the function of the glutamine transporter in S. mutans MT8148.
Methods
The SMU.732 gene, corresponding to glnP in S. mutans, is homologous to the glutamine transporter gene in Bacillus subtilis. We constructed a glnP-inactivated mutant strain (GEMR) and a complement strain (comp-GEMR) and evaluated their biological functions.
Results
Growth of GEMR was similar in the presence and absence of glutamine, whereas the growth rates of MT8148 and comp-GEMR were significantly lower in the presence of glutamine as compared to its absence. Furthermore, biofilms formed by MT8148 and comp-GEMR were significantly thicker than that formed by GEMR, while the GEMR strain showed a significantly lower survival rate in an acidic environment than the other strains. Addition of n-phenyl-2-naphthylamine, used to label of the membrane, led to increased fluorescence intensity of MT8148 and GEMR, albeit that was significantly lower in the latter.
Conclusions
These results suggest that glnP is associated with glutamine transport in S. mutans, especially the import of glutamine involved in biofilm formation. en-copyright= kn-copyright= en-aut-name=MorikawaYuko en-aut-sei=Morikawa en-aut-mei=Yuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MorimotoSetsuyo en-aut-sei=Morimoto en-aut-mei=Setsuyo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YoshidaEri en-aut-sei=Yoshida en-aut-mei=Eri kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NakaShuhei en-aut-sei=Naka en-aut-mei=Shuhei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=InabaHiroaki en-aut-sei=Inaba en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=Matsumoto-NakanoMichiyo en-aut-sei=Matsumoto-Nakano en-aut-mei=Michiyo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Department of Pediatric Dentistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences kn-affil= affil-num=2 en-affil=Department of Pediatric Dentistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences kn-affil= affil-num=3 en-affil=Department of Pediatric Dentistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences kn-affil= affil-num=4 en-affil=Department of Pediatric Dentistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences kn-affil= affil-num=5 en-affil=Department of Pediatric Dentistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences kn-affil= affil-num=6 en-affil=Department of Pediatric Dentistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences kn-affil= en-keyword=Streptococcus mutans kn-keyword=Streptococcus mutans en-keyword=glutamine transporter kn-keyword=glutamine transporter en-keyword=biofilm kn-keyword=biofilm en-keyword=membrane protein kn-keyword=membrane protein en-keyword=glnP kn-keyword=glnP END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2014 dt-pub=20140102 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Cross-cultural validity of a dietary questionnaire for studies of dental caries risk in Japanese en-subtitle= kn-subtitle= en-abstract= kn-abstract=Background: Diet is a major modifiable contributing factor in the etiology of dental caries. The purpose of this paper is to examine the reliability and cross-cultural validity of the Japanese version of the Food Frequency Questionnaire to assess dietary intake in relation to dental caries risk in Japanese. Methods: The 38-item Food Frequency Questionnaire, in which Japanese food items were added to increase content validity, was translated into Japanese, and administered to two samples. The first sample comprised 355 pregnant women with mean age of 29.2 +/- 4.2 years for the internal consistency and criterion validity analyses. Factor analysis (principal components with Varimax rotation) was used to determine dimensionality. The dietary cariogenicity score was calculated from the Food Frequency Questionnaire and used for the analyses. Salivary mutans streptococci level was used as a semi-quantitative assessment of dental caries risk and measured by Dentocult SM. Dentocult SM scores were compared with the dietary cariogenicity score computed from the Food Frequency Questionnaire to examine criterion validity, and assessed by Spearman's correlation coefficient (r(s)) and Kruskal-Wallis test. Test-retest reliability of the Food Frequency Questionnaire was assessed with a second sample of 25 adults with mean age of 34.0 +/- 3.0 years by using the intraclass correlation coefficient analysis. Results: The Japanese language version of the Food Frequency Questionnaire showed high test-retest reliability (ICC = 0.70) and good criterion validity assessed by relationship with salivary mutans streptococci levels (r(s) = 0.22; p < 0.001). Factor analysis revealed four subscales that construct the questionnaire (solid sugars, solid and starchy sugars, liquid and semisolid sugars, sticky and slowly dissolving sugars). Internal consistency were low to acceptable (Cronbach's alpha = 0.67 for the total scale, 0.46-0.61 for each subscale). Mean dietary cariogenicity scores were 50.8 +/- 19.5 in the first sample, 47.4 +/- 14.1, and 40.6 +/- 11.3 for the first and second administrations in the second sample. The distribution of Dentocult SM score was 6.8% (score = 0), 34.4% (score = 1), 39.4% (score = 2), and 19.4% (score = 3). Participants with higher scores were more likely to have higher dietary cariogenicity scores (p < 0.001; Kruskal-Wallis test). Conclusions: These results provide the preliminary evidence for the reliability and validity of the Japanese language Food Frequency Questionnaire. en-copyright= kn-copyright= en-aut-name=Shinga-IshiharaChikako en-aut-sei=Shinga-Ishihara en-aut-mei=Chikako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NakaiYukie en-aut-sei=Nakai en-aut-mei=Yukie kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MilgromPeter en-aut-sei=Milgrom en-aut-mei=Peter kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MurakamiKaori en-aut-sei=Murakami en-aut-mei=Kaori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=Matsumoto-NakanoMichiyo en-aut-sei=Matsumoto-Nakano en-aut-mei=Michiyo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Okayama Univ, Grad Sch Med Dent & Pharmaceut Sci, Dept Pediat Dent affil-num=2 en-affil= kn-affil=Okayama Univ, Grad Sch Med Dent & Pharmaceut Sci, Dept Pediat Dent affil-num=3 en-affil= kn-affil=Univ Washington, Dept Oral Hlth Sci affil-num=4 en-affil= kn-affil=Okayama Univ, Grad Sch Med Dent & Pharmaceut Sci, Dept Pediat Dent affil-num=5 en-affil= kn-affil=Okayama Univ, Grad Sch Med Dent & Pharmaceut Sci, Dept Pediat Dent en-keyword=Food frequency questionnaire kn-keyword=Food frequency questionnaire en-keyword=Cariogenic food kn-keyword=Cariogenic food en-keyword=Diet kn-keyword=Diet en-keyword=Reliability kn-keyword=Reliability en-keyword=Validity kn-keyword=Validity en-keyword=Mutans streptococci kn-keyword=Mutans streptococci END