Mi-Ah Kim

Functional Relationship between Sucrose and a Cariogenic Biofilm Formation.

Sucrose is an important dietary factor in cariogenic biofilm formation and subsequent initiation of dental caries. This study investigated the functional relationships between sucrose concentration and Streptococcus mutans adherence and biofilm formation. Changes in morphological characteristics of the biofilms with increasing sucrose concentration were also evaluated. S. mutans biofilms were formed on saliva-coated hydroxyapatite discs in culture medium containing 0, 0.05, 0.1, 0.5, 1, 2, 5, 10, 20, or 40% (w/v) sucrose. The adherence (in 4-hour biofilms) and biofilm composition (in 46-hour biofilms) of the biofilms were analyzed using microbiological, biochemical, laser scanning confocal fluorescence microscopic, and scanning electron microscopic methods. To determine the relationships, 2nd order polynomial curve fitting was performed. In this study, the influence of sucrose on bacterial adhesion, biofilm composition (dry weight, bacterial counts, and water-insoluble extracellular polysaccharide (EPS) content), and acidogenicity followed a 2nd order polynomial curve with concentration dependence, and the maximum effective concentrations (MECs) of sucrose ranged from 0.45 to 2.4%. The bacterial and EPS bio-volume and thickness in the biofilms also gradually increased and then decreased as sucrose concentration increased. Furthermore, the size and shape of the micro-colonies of the biofilms depended on the sucrose concentration. Around the MECs, the micro-colonies were bigger and more homogeneous than those at 0 and 40%, and were surrounded by enough EPSs to support their structure. These results suggest that the relationship between sucrose concentration and cariogenic biofilm formation in the oral cavity could be described by a functional relationship.

Rapid Detection of S. Mutans Surface Antigen I/II Using a Sensitive Monoclonal Anti-Ag I/II Antibody by ELISA

The cell-surface protein antigen I/II (Ag I/II) is expressed in oral streptococci, which are known as the causative agent of a number of diseases including dental caries, endocarditis, gingivitis, and periodontal disease. Consequently, monoclonal antibodies (MAb) capable of recognizing the streptococcal Ag I/II protein could be a useful tool for the diagnosis and cure of these diseases. In this study, a previously generated monoclonal anti-Ag I/II antibody, ckAg I/II, was used to detect a small amount of Streptococcus mutans (S. mutans) surface antigen Ag I/II. The ckAg I/II was proved to be very sensitive and able to detect as little as 1 ng of recombinant Ag I/II protein within 5 min and Ag I/II in saliva within 10 min, as well as native Ag I/II in 20 μL of culture supernatant by ELISA. These results suggest that ckAg I/II can be used as a fast and efficient diagnostic tool to detect Ag I/II.

Development of a Monoclonal Antibody Against Glucosyltransferase D of Streptococcus mutans GS 5

Glucosyltransferases GtfB, GtfC, and GtfD of Streptococcus mutans are virulent factors involved in dental caries. Consequently, they are considered to be target molecules in the development of vaccines against dental caries. Among them, GtfD plays a significant role in the sucrose-dependent cellular adhesion of S. mutans, and a number of studies have suggested that the N-terminus of GtfD is an important part of its role in enzymatic activity. In this study, we generated monoclonal antibodies against the N-terminus of GtfD (anti-GtfDN antibody) in an initial attempt to investigate its preventive efficacy against dental caries. To obtain anti-GtfDN monoclonal antibodies, the gene for the N-terminus of gtfD (2 kb) was cloned into an Escherichia coli expression vector, pQE30; then the expressed protein (about 75 kDa) was purified. The purified GtfDN protein was injected into BALB/c mice, and hybridoma clones were established. We obtained three hybridoma clones (HDN9, HDN11, and HDN28) capable of producing anti-GtfDN antibodies. Their binding specificity was characterized by ELISA, dot blot, and Western blot analysis after purification using affinity column chromatography. The isotype of the monoclonal antibodies was confirmed to be IgG2a.

A Monoclonal Antibody Specific to Glucosyltransferase B of Streptococcus mutans GS-5 and Its Glucosyltransferase Inhibitory Efficiency

Glucosyltransferase-B (GTFB) of Streptococcus mutans is considered a virulence factor because of its activity in the production of insoluble glucan, which is key to the bacterial attachment onto dental surfaces, leading to the formation of dental caries. Local passive immunization with monoclonal antibodies against GTFB is considered to be an effective way to prevent dental caries. Here we amplified a 1.3 kb fragment of the N-terminal half of the gtfB gene (193-1530) of S. mutans by PCR and expressed the truncated protein (GTFBN). The expressed, purified protein was used as an immunogen in BALB/c mice. We selected and established one hybridoma (HBN8) that was capable of producing anti-GTFBN using ELISA, dot blot, and Western blot analyses. The monoclonal anti-GTFBN antibody was purified by affinity chromatography and its isotype was confirmed as IgG2a. The anti-GTFBN antibody inhibited the enzymatic activity of crude glucosyltransferase of S. mutans GS-5 in a dose-dependent manner. These data suggest that the anti-GTFBN antibody could be used as a vaccine to prevent the aggregation of S. mutans on tooth surfaces, and thus prevent the formation of dental caries.

Detection of Streptococcus mutans in Saliva using Monoclonal Antibodies

본 연구의 목적은 Streptococcus mutans의 Ag I/II와 glucosyltransferase에 대해 개발된 단일클론항체를 사용한 타액 내 Streptococcus mutans 검출의 효용성을 평가하기 위함이다. 세 군(성인, 미성년자, 그리고 교정치료중인 미성년자)을 대상으로 DMFT,

Rapid Detection of Pathogens Associated with Dental Caries and Periodontitis by PCR Using a Modified DNA Extraction Method

Dentocult^{(R)}

Monoclonal Antibodies Specific to Streptococcus mutans GS-5 Glucosyltransferase-C Inhibit Bacterial Glucosyltransferase

-SM strip mutans를 이용한 타액내의 colony density (CFU/mL), polymerase chain reaction을 이용한 Sreptococcus mutans와 Sreptococcus sobrinus의 존재여부, 그리고 4가지 단일클론항체를 사용한 타액 내 Streptococcus mutans 검출 실험을 시행하였다. 그 결과 Streptococcus mutans가 Streptococcus sobrinus보다 치아우식 형성에 더 주요하게 작용한다는 것을 입증하였으며, glucosyltransferases (gtf B, gtf C, gtf D)와 Ag I/II에 대한 단일클론항체들의 Streptococcus mutans를 검출해 내는 능력이

DISTRIBUTION AND TRANSMISSION OF STREPTOCOCCUS MUTANS AMONG CHILDREN AND THEIR MOTHERS

Dentocult^{(R)}

SPONTANEOUS ERUPTION OF PERMANENT TEETH AFTER MARSUPIALIZATION ASSOCIATED WITH DENTIGEROUS CYSTS

-SM strip mutans나 polymerase chain reaction을 사용한 검출법보다 뛰어남을 보였다. 【The purpose of this study was to determine the usefulness of a detection method for Streptococcus mutans in saliva with monoclonal antibodies developed targeting Ag I/II and glucosyltransferases (gtf B, gtf C and gtf D) in Streptococcus mutans. In the three groups tested (adults, minors, and minors under orthodontic treatment), the results of the DMFT scores, the colony density (CFU/mL) in their saliva was measured using

Streptococcus mutans extracellular DNA levels depend on the number of bacteria in a biofilm

Dentocult^{(R)}