• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.304-313
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• 2004

Xylitol, a five-carbon natural sugar alcohol, is widely used non-cariogenic sugar substitute. In present study, the effects of xylitol on the expression of mRNA for glucosyltransferase which synthesizes glucan from sucrose were detected by Fluorescent in situ hybridization (FISH) and flow cytometry. FITC fluorescences for mRNA of gtfB, gtfC and gtfD were decreased further with increasing concentration of xylitol from 1% to 10% when detected by FISH. Flow cytometric analysis also showed that the expression of gtfB, gtfC and gtfD was increased by the addition of sucrose and decreased by the addition of xylitol to BHI broth containing 1% sucrose. In conclusion, the expression of gtfB, gtfC and gtfD mRNA was decreased by the addition of xylitol.

• International Journal of Oral Biology
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• v.44 no.2
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• pp.31-36
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• 2019

Streptococcus mutans is one of the important bacteria that forms dental biofilm and cause dental caries. Virulence genes in S. mutans can be classified into the genes involved in bacterial adhesion, extracellular polysaccharide formation, biofilm formation, sugar uptake and metabolism, acid tolerance, and regulation. The genes involved in bacterial adhesion are gbps (gbpA, gbpB, and gbpC) and spaP. The gbp genes encode glucan-binding protein (GBP) A, GBP B, and GBP C. The spaP gene encodes cell surface antigen, SpaP. The genes involved in extracellular polysaccharide formation are gtfs (gtfB, gtfC, and gtfD) and ftf, which encode glycosyltransferase (GTF) B, GTF C, and GTF D and fructosyltransferase, respectively. The genes involved in biofilm formation are smu630, relA, and comDE. The smu630 gene is important for biofilm formation. The relA and comDE genes contribute to quorumsensing and biofilm formation. The genes involved in sugar uptake and metabolism are eno, ldh, and relA. The eno gene encodes bacterial enolase, which catalyzes the formation of phosphoenolpyruvate. The ldh gene encodes lactic acid dehydrogenase. The relA gene contributes to the regulation of the glucose phosphotransferase system. The genes related to acid tolerance are atpD, aguD, brpA, and relA. The atpD gene encodes $F_1F_0$-ATPase, a proton pump that discharges $H^+$ from within the bacterium to the outside. The aguD gene encodes agmatine deiminase system and produces alkali to overcome acid stress. The genes involved in regulation are vicR, brpA, and relA.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.8-16
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• 2013

A GAL4 type transcription factor gene (formally annotated as AN3912) locating downstream of sndA (AN3911) was characterized. The putative transcription factor carries both Zn(II)2Cys6 binuclear cluster DNA-binding domain and transcription activator domain. The gene named gtfA (gal4 type transcription factor) had an open reading frame which consisted of 762 amino acids and was disrupted by three introns. The deletion mutant produced reduced amount of conidia but increased amount of fruiting bodies, suggesting that the GtfA make function in decision of asexual preferential to sexual development. The forced over expression of gtfA caused the retardation of fruiting body formation on high glucose concentration. The transcript level of gtfA was kept constant through the life cycle except late vegetative stage and early sexual development stage during which slight increase was found. The expression of gtfA was not significantly affected by sexual or asexual development regulators, such as VeA, NsdD or FluG, FadA, and SfaD. The GtfA repressed the nsdC transcription, which suggested that GftA control sexual development negatively via negative regulation of nsdC expression.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.151-158
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• 2023

Erythritol is a sweetener produced by yeast from glucose and a natural sugar found in fermented foods such as mushrooms, wine, fruits, rice wine, and soy sauce. Correct information and basic data when producing or using products for preventing dental caries by checking the gene expression patterns of glucosyl transferase (GTF) and fructosyl transferase (FTF) of Streptococcus mutans in erythritol and other sweeteners it was implemented to provide. Erythritol inhibited the growth of Streptococcus mutans, which is involved in dental caries. When used as a sweetener to replace sucrose, erythritol had an excellent caries-preventative effect. In particular, erythritol reduced the expressions of gtfB, gtfC, gtfD, and FTF, which are related to the synthesis of extracellular polysaccharides, and thereby reduced the formation of dental plaque and the attachment rate of bacteria to tooth surfaces. The study shows erythritol has potential use as an anticariogenic sweetener that inhibits the mechanism underlying caries caused by Streptococci.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2990-2996
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• 2009

S. mutans, one of a major causal agents of dental caries, is component of the dental plaque and produces various organic acids such as lactic acid as the end-product of glycolysis. In this study, we are interested in comparing the gene expression of acid-shocked and control cells of S. mutans isolated from Korean with caries. Expression levels of gtfB, gtfC, gtfD and ftf were analyzed by Real-time PCR, when the cells were grown under 20 mM lactic acid stress in the exponential phase. The data showed reduced expression of these genes. S. mutans is known to have developed a variety of mechanisms to tolerate acid sterss. A more detailed analysis of the functions and interactions of acid stress proteins connecting the growth, stress tolerance, biofilm formation is under way.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.531-538
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• 2009

Xylitol has the ability to reduce the adherence of Streptococcus mutans(S. mutans), which can make it easier to remove plaque, decrease acid production and inhibit dental caries. There are few reports on the effects of xylitol on the expression of the virulence related genes in S. mutans. This study examined the inhibitory effect of chewing gum containing xylitol on glucan synthesis related gene expression of S. mutans. Participants were voluntarily recruited for a women's oral health prevention program, classified into two groups(a control and a xylitol group), and then followed for 2 years. Twenty salivary samples were randomly selected from each group. Colony count and real-time reverse transcription polymerase chain reaction were used to analyze the characteristics of S. mutans. The following results were obtained: The S. mutans counts decreased steadily in the xylitol group over the study period(p<0.05). The expression of the virulence related genes (gtfB, gtfC and gtfD) was significantly lower in the xylitol group than in the control groups (p<0.05). In conclusion, these results suggest that chewing xylitol gum for a long period of time may reduce the expression of the genes associated with S. mutans virulence, which can result in a decrease growth of S. mutans colonies as a result.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.314-322
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• 2004

The production of a glucan was affected by the concentration of ions and buffer solutions, and nutrients in an oral cavity. In this study, the effects of ions and buffer solutions on the mRNA expression of gtfD gene in Streptococcus mutans, an important causative agent of dental caries, were investigated by Fluorescent in situ hybridization(FISH). At first, ions and buffer solutions had little effect on the multiplication of Streptococcus mutans. The green fluorescence according to the mRNA expression of gtfD gene was detected in the BHI broth containing 1% sucrose. The intensities of the green fluorescence were strong at 0.25mM of $CaCl_2$. Little fluorescence was detected by the addition of KCl, except far 10mM KCl at which fluorescence intensities were similar to those of the control. Fluorescence intensities were weak at each concentration of $MgCl_2$ when compared to the control. As for buffer solutions, fluorescence intensities were similar to those of the control at each concentration of buffer solutions, except that they were little detected at 100mM of potassium phosphate.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.498-500
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• 2009

본 연구에서는 한국인 아동의 우식치아로부터 분리한 S. mutans K7으로부터 HtrA gene을 동정하고 HtrA expression이 산성환경하에서 S. mutans의 생육에 미치는 영향을 알아보았다. S. mutans K7의 HtrA mutant strain은 산성환경에서 parental strain과 비교하였을 때, 생육에 있어서 상당한 차이를 나타내었다. 또한 Biofilm formation에 관여하는 GtfB, 와 GtfC의 발현량도 현저히 줄어들었다. 그리고 HtrA mutant strain에 HtrA gene을 삽입하여 HtrA의 발현량을 회복하였을 경우에는 acid stress하에서 control과 같은 nomal growth phenotype을 회복하였다. 이러한 결과들은 S. mutans K7에서 HtrA가 acid stress동안에 중요한 역할을 담당함을 제시하고 있다.

• Journal of Life Science
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• v.29 no.1
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• pp.90-96
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• 2019

The objective of this study was to evaluate the potential of Diospyros malabarica stem extract, a natural materials, in oral health material. With this aim in mind, thin layer chromatography (TLC), TLC-bioautography, high-performance liquid chromatography (HPLC), electrospray ionization-mass spectrometry (ESI-MS), scanning electron microscopy (SEM), and real-time qPCR were performed. The antibacterial activity of D. malabarica stem extract against Streptococcus mutans KCTC3065 was confirmed in an n-hexane fraction with low polarity. The molecular weight of the antibacterial compound was estimated to be 188 by ESI-MS analysis. The inhibitory effects of the extract on biofilm formation and gene expression related to biofilm formation of S. mutans were determined by SEM and real-time PCR analysis. The extract inhibited the formation of S. mutans biofilms at D. malabarica stem extract concentrations of 1 mg/ml, as shown by SEM. The real-time PCR analysis showed that the expression of the gtfC gene, which is associated with biofilm formation, was significantly decreased in a dose-dependent manner. Based on the above results, it can be concluded that D. malabarica stem extracts, a natural materials, can be used in oral health products to suppress the formation of biofilms by inhibiting tooth adhesion of S. mutans, a causative agent of dental caries.

• Journal of Plant Biotechnology
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• v.36 no.1
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• pp.87-95
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• 2009

The recombinant DNAs, pGBF, pGTF, and pZ4F, using soybean ferritin gene have constructed with the promoters derived from seed proteins, glutelin, globulin, and zein. The recombinant ferritin genes were transformed into rice plant by Agrobacterium-mediated transformation. Iron contents and agronomic traits have been evaluated in the transgenic progenies. The embryogenic calli survived from second selection medium were regenerated at the rates of 19.2% with pGBF, 15.0% with pGTF, and 18.4% with pZ4F in Donganbyeo and 6.7% with pGBF, 11.7% with pGTF, and 3.4% with pZ4F in Hwashinbyeo. The introduction of ferritin gene in putative transgenic rice plants was confirmed by PCR and Southern blot analysis and also the expression of ferritin gene was identified by Northern blot and Western blot analysis. The iron accumulation in transgenic rice grains of the transgenic rice plant, T1-2, with zein promoter and ferritin gene contained 171.4 ppm showing 6.4 times higher than 26.7 ppm of Hwashinbyeo seed as wild type rice, but the transgenic plants with globulin and glutelin showed a bit higher iron contents with a range from 2.1 to 3.0 times compare to wild type grain. The growth responses of transgenic plants showed the large variances in plant height and number of tillers. However, there were some transgenic plants having similar phenotype to wild type plants. In the T1 generation of transgenic plants, plant height, culm length, panicle length, and number of tillers were similar to those of wild type plants, but ripened grain ratio ranged from 53.3% to 82.2% with relatively high variation. The transgenic rice plants would be useful for developing rice varieties with high iron content in rice grains.