• International Journal of Oral Biology
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• v.39 no.2
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• pp.65-73
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• 2014

Chios Gum Mastic (CGM) is a natural resin extracted from the leaves of Pistacia lentiscus, a plant endemic to the Greek island of Chios. It has been used by traditional healers, and it has antibacterial, antifungal properties, and therapeutic benefits for the skin. The CGM reduces the formation of dental plaque and bacterial growth in oral saliva, and recent studies have demonstrated the role of antioxidant activity of CGM. Although CGM has been widely investigated, its protective effect against oxidative-damage to keratinocytes, as well as the relationship between CGM and autophagy, has not been investigated. The aim of this study was to assess the protective effect of CGM against $H_2O_2$-induced oxidative stress and to evaluate the autophagic features induced by CGM in human keratinocytes. The pretreatment with CGM significantly reduced apoptosis in $H_2O_2$-exposed HaCaT cells. It promoted the degradation of caspase-3, caspase-8, and caspase-9; and it induced the formation of the processed PARP. The treatment with CGM caused an increase in vesicle formation compared to control group. The level of p62 was reduced and the conversion of LC3-I to LC3-II was increased in CGM treated HaCaT cells. Also, the treatment with CGM increased cleavage of ATG5-ATG12 complex. In summary, CGM helps the cells to survive under stressful conditions by preventing apoptosis and enhancing autophagy. Besides, the present investigation provides evidence to support the antioxidant potential of CGM in vitro and opens up a new horizon for future experiments.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.126-134
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• 2001

Background : Paeonia japonica Miyabe is a medicinal plant which has been widely used as a component of blood-building decoctions (Chinese medicinal concept : Bu-Xie). The immunopharmacological characteristics of the extract of Paeonia japonica (PJ) were investigated. Methods : The effects of fractions of PJ extract on lymphocyte proliferation were measured by $H^3$-thymidine incorporation assay. The proliferated lymphocyte subsets were analyzed in flow cytometry. The subset cell populations of spleen cells were separated by magnetic cell separation system, and their proliferation by the extract were investigated. The effect of the extract on antibody production was determined in mice challenged with sheep red blood cells (SRBC) using hemolytic plaque forming cell assay. Results : Spleen cells were proliferated by water extract of PJ. Polysaccharide fraction (PJ-P) of the extract was most active in the proliferation. It was found in flow cytometry that the lymphocyte subset proliferated by PJ-P was B cell population. Among the separated subset cell populations, T cell-depleted cell population and macrophage-depleted cell population were most proliferated by PJ-P. However, positively selected populations of B cells and T cells were not proliferated by PJ-P. These results indicate that B cell proliferation by PJ-P may require the assistance of macrophages or T cells. These results suggest that firstly PJ-P may stimulate macrophages or T cells, and then B cells are activated. The number of antibody-secreting cells was increased by administration of PJ-P in mice immunized with SRBC as a T-dependent antigen. Conclusion : These results suggest that macrophages and accessory cells are directly activated by PJ-P and then helper T cells and B cells are indirectly activated. As the results, immune responses might be coordinately improved. In conclusion, PJ-P, a polysaccharide of P. japonica, may be a characteristic immunostimulator, which is analogous to polysaccharides such as lentinan, PSK and ginsan.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.30-37
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• 2015

A new colorimetric test ($Cariview^{(R)}$) using a new type of pH indicator can reflect the acidogenic potential of plaque bacteria. The objective of this study was to evaluate the correlation between $Cariview^{(R)}$ and the caries experience (measured through the dmft index) of children, and to compare $Cariview^{(R)}$ with Dentocult $SM^{(R)}$. Having obtained informed consent, 135 children less than 6 years old participated in the study. We examined their dmft index, and performed two caries activity tests ($Cariview^{(R)}$ and Dentocult $SM^{(R)}$) according to the manufacturers' instructions. In the results, $Cariview^{(R)}$ showed a moderate correlation with the dmft index (r = 0.43, p < 0.01). $Cariview^{(R)}$ showed a sensitivity of 68.8%, a specificity of 69.2%, and an area under curve of 0.686 in the ROC curve analysis. $Cariview^{(R)}$ had a significant correlation with the children's caries experience and had a slightly better explanatory ability than Dentocult $SM^{(R)}$. Furthermore, $Cariview^{(R)}$ was convenient and easy to use on uncooperative children, and also had an educational effect with its visual colors. It is suggested that $Cariview^{(R)}$ could be used clinically to identify the children susceptible to develop caries and to establish a preventive strategy.

• Journal of dental hygiene science
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• v.7 no.1
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• pp.21-24
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• 2007

Dental caries is initiated by the acid accumulated in dental plaque. Streptococcus 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. As a consequence, we investigated the acid stress response of S. mutans KCTC 3065 in this study. The addition of lactic acid to the growth media had a concentration-dependent effect on the growth of S. mutans. S. mutans exhibited higher maximum culture OD compared with the more acidic growth pH values. At treatment of centration of 20 mmol/L lactic acid in the mid-log phage, cell growth was reduced to 40% relative to the control. The following results were obtained with the treatment of cells with a concentration of 20 mmol/L lactic acid in the mid-log phage for 2hrs: Analysis of fatty acids extracted from cells showed that growth at a concentration of 20 mmol/L lactic acid resulted in changes in $C_{14:0}$, $C_{16:0}$, $C_{18:0}$ and $C_{18:1}$ fatty acids. Protein profiles investigated by SDS-PAGE showed that approximately 70, 60, 45, 40 and 23 kDa proteins were highly expressed in S. mutans KCTC 3065.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.554-562
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• 2003

Xylitol has been used as sugar substitute to prevent dental caries. It is not fermented by most dental plaque bacteria and interferes with the growth of mutans streptococci. Therefore the production of acidic metabolites and the growth of mutans streptococci are inhibited. S. mutans strains which are inhibited to grow under the presence of xylitol are referred as xylitol-sensitive ($X^S$) strains. However, experimental and clinical studies have shown that there were mutated groups of S. mutans strains that are not affected by xylitol. They are referred as xylitol-resistant($X^R$) strains. The aim of the present study was to investigate that emergence of $X^R$ strain would effect on the anticariogenecity of xylitol by comparing the growth rate, the extracellular pH, hydroxyapatite adhesion and the agglutination of the $X^R/X^S$ strains. Overall we came out with following results : 1. No difference in the growth rate and the extracellular pH was found between the $X^S$ strain and the $X^R$ strain. 2. No difference in adhesion to hydroxyapatite surface was found between the $X^R$ strain and the $X^S$ strain (p>0.05) and adhesion of the $X^S$ strain was greater than that of $X^R$ strain in the sucrose-dependent adhesion to hydroxyapatite (p<0.05). 3. The $X^R$ strain was agglutinated in the lower concentration of saliva than that of $X^S$ strains.

• Biomedical Science Letters
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• v.16 no.3
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• pp.201-206
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• 2010

In order to develop procedures for the rapid isolation of recombinant sugar transporter in functional form from away from the endogenous insect cell transporter, gene fusion techniques were exploited. Briefly, BamH1-digested human HepG2 type glucose transport protein cDNA was first cloned into a transfer vector pBlueBacHis, containing a tract of six histidine residues. Recombinant baculoviruses including the human cDNA were then generated by allelic exchange following transfection of insect cells with wild-type BaculoGold virus DNA and the recombinant transfer vector. Plaque assay was then performed to obtain and purify recombinant viruses expressing the human transport protein. All the cell samples that had been infected with viruses from the several blue plaques exhibited a positive reaction in the immnuassay, demonstrating expression of the glucose transport protein. In contrast, no color development in the immunoassay was observed for cells infected with the wild-type virus or no virus. Immunoblot analysis showed that a major immunoreactive band of apparent Mr 43,000~44,000 was evident in the lysate from cells infected with the recombinant baculovirus. Following expression of the recombinant fusion protein with the metal-binding domain and enterokinase cleavage site, the fusion protein was recovered by competition with imidizole using immobilized metal charged resin. The leader peptide was then removed from the fusion protein by cleavage with porcine enterokinase. Final separation of the recombinant protein of the interest was achieved by passage over $Ni^{2+}$-charged resin under binding conditions. The expressed transport protein bound cytochalasin B and demonstrated a functional similarity to its human counterpart.

• Journal of Korean society of Dental Hygiene
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• v.12 no.1
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• pp.27-35
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• 2012

Objectives : This study was performed to provide the basic data for oral health of infants, through the comparison of Streptococcus mutans activities(the representative bacteria of initial dental caries), in main nutritional foods for infants: breast milk, milk powder, and soya milk. Methods : The study targeted 30 infants and the saliva was sampled after the oral examination. The pH of sampled saliva was measured; and the sample of 'the saliva', 'the saliva and breast milk', and 'the saliva and formula milk' by researcher were produced; and the measurement was repeated 7 times. Results : As a result of examining the change of colony number of Streptococcus mutans by hour, the bacterial activity took in the source of nutrition took place in the first place; and in the group with dental caries, breast-feeding at night occurreds most frequently. Due to the combined activities, such as the increase in the contact time, the existence rate of dental caries appeared high. However, as the improvement of breast-feeding is closely related to the nutrition supply to babies, rather than the improvement of breast-feeding, the 12 hours after the culture in which Streptococcus mutans activities started was considered. Conclusions : In case of breast-feeding at night, it is necessary to remove the dental plaque in the mouth, before 12 hours has passed. Especially, using toothbrush and toothpaste to decrease the occurrence of dental caries, after the eruption of teeth, is recommended for oral administration.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.838-842
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• 2004

Amyloid peptide (A${\beta}$) is the major component of senile plaques found in the brain of patient of Alzheimer's disease. ${\beta}$-amyloid peptide (25-35) (A${\beta}$25-35) is biologically active fragment of A${\beta}$. The three-dimensional structure of A${\beta}$25-35 in aqueous solution with 50% (vol/vol) TFE determined by NMR spectroscopy previously adopts an ${\alpha}$-helical conformation from $Ala^{30}$ to $Met^{35}$. It has been proposed that A${\beta}$(25-35) exhibits pH- and concentration-dependent ${\alpha}-helix{\leftrightarrow}{\beta}$sheet transition. This conformational transition with concomitant peptide aggregation is a possible mechanism of plaque formation. Here, in order to gain more insight into the mechanism of ${\alpha}$-helix formation of A${\beta}$25-35 peptide by TFE, which particularly stabilizes ${\alpha}$-helical conformation, we studied the secondary-structural elements of A${\beta}$25-35 peptide by molecular dynamics simulations. Secondary structural elements determined from NMR spectroscopy in aqueous TFE solution are preserved during the MD simulation. TFE/water mixed solvent has reduced capacity for forming hydrogen bond to the peptide compared to pure water solvent. TFE allows A${\beta}$25-35 to form bifurcated hydrogen bonds to TFE as well as to residues in peptide itself. MD simulation in this study supports the notion that TFE can act as an ${\alpha}$-helical structure forming solvent.

• Korean Journal of Microbiology
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• v.17 no.3
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• pp.97-130
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• 1979

Many industrial processes those employ bacteria are subjected to phage infestations. In L-glutamic acid fermentions using acetic acid, the phage infestations of the organisms have been recently recognized. In efforts to elucidate the sources of phage contamination involved in the abnormal fermentation, a series of study was conducted to isolate the phages both from the contents of abnormally fermented tanks and the soil or sewage samples from the surroundings of a fermentation factory, to define major charateristics of the phage isolates, and finally to determine the correlation between the phage isolates and temperate phages originating from the miscellaneous bacterial species isolated from the soil or sewage samples. The results are summarized as follows; 1) All phages were isolated from the irregular fermentation tanks and soil or sewage samples, and they were designated as phage PR-1, PR-2, PR-3, PR-4, PR-5, PR-6, and PR-7, in the order of isolation. These PR-series phages were proved to be highly specific for the variant strains of Br. lactofermentum only, namely, phage PR-1 and PR-2 for Br. lactofermentum No. 468-5 and phage PR-3~PR-7 for Br. lactofemrentum No. 2256. By cross-neutralization test, the 7 phagescould be subdivided into 3 groups, i. e., phage PR-I and PR-2 the first, phage PR-3, PR-4, PR-5, PR-6 the second, and the phage PR-7 the third. 2) The 7 phages were virulent under the experimental conditions. They produced plaques with clear and relatively sharp margins without distinct halo. The mean sizes of plaques were 1.5mm in diameter for phage PR-1 and PR-2, and 1. Omm for phages PR-3~PR-7. Double layer technique modified by Hongo and described by Adams, was applied to assay of the PR-series phages. The factors influencing the plaques were as follows;young age cells of host bacteria cultured for 3-6 hours represented the largest number and size, optimum was pH 7.0, incubation temperature was $30^{\circ}C$, and agar concentration and amount of overlayer medium were 0.6% and 0.2ml, respectively. 3) PR-series phages were stable in 0.05M tris buffer and 0.1M ammonium acetate buffer solution. The addition of $5{\times}10^{-3}M$ magnesium ion effectively increased the stability. Thermostability experiments indicated that PR-series phages were stable at the teinperture between $50^{\circ}{\sim}55^{\circ}C$ in nutrient medium, $45^{\circ}{\sim}50^{\circ}C$ in buffer solution. However, the phages mere completely inactivated at 603C and 65$^{\circ}$C within 10 minutes. The phages were stable at the range of pH6~9 in nutrient medium and of pH 8-9 in buffer solution, respectively. Exposure of the phages to UV for 25, 60 and 100 seconds resulted in the complete loss of infectivily, respectively. 4) Electron microscopy showed that PR-series phage particles exhibited rather similar morphology, differing in the size All of PR-series phages had a multilateral head and had a simple long tiil about three to five times long as compared with head. By the size, phage PR-1 and PR-2, PR-3, PR-4, PR-5, and PR-6 and PR-7 were classified into same groups, respectively. The head and tail size of phage PR-1, PR-5, PR-5(T) and PR-7 were 85nm, 74nm and 235nm and 350mm, and 72nm and 210nm, respectively. 5) Nucleic acids of PR-series phages were double stranded DNA. The G+C contents of phage PR-1, PR-5 and PR-7 were 56.1, 52.9 and 53.7, respectively. The values of G+C contents derived from the $T_m$ were in agreement with the chemically determined values. 6) PR-series phages effectively adsorbed on their host bacteria at the rate of more than 90% during 5 min. K value for phage PR-1, PR-5 and PR-7 were calculated to be $6{\times}10^9 ml$ per minute, respectiveky. The pH of the medium did effect adsorption rate, but both temperature and age of host cells did not. Generally, optimum adsorption condition of phages seemed to be almost same as optimum growth conditions of host bacteria. 7) In one-step growth experiments, the latent periods at $30^{\circ}C$ for PR-1, and PR-7 were about 70, 50 and 55 min, respectively. The corresponding average burst size was 200, 70 and 90, respectively. Lpsis period according to the multiplicity of infection and a phage series. In case of m. o. i. 100, strain No. 2256 (PR-5) and No. 468-5(PR-1) failed to grow and turbidity decreased after 50 and 70min, respectively. 8) In the lysate of a plaque purified phage PR-5 infected bacteria, there observed 2 types ofphage particles, i. e., phage PR-5 and PR-5 (T) of similar morphology but differing at the length of phage tail, and phage tail like particles. The phage taillike particles could be divided into 4 types by the length. Induction experiments of Br. lactofermentum with UV irradiation, mitomycin C or bacitracin treatment produced neither phage PR-5 (T) or phage tail-like particles. 9) No lysis occured when the growth of 7 strains of miscellaneous bacteria, isolated from soil and sewage samples, were inoculated with either phage PR-5 (T) or phage tail-like particles the inoculation of phage PR-5 pellet resulted in the growth inhibition of the orgainsms in the spot test. The lysates obtained from 3 miscellaneous soil derived bacteria following mitomycin C treatment the growth of Br. lactofermentum, but did not lyze the bacterium.

• The Journal of the Korean dental association
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• v.55 no.6
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• pp.413-422
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• 2017

Purpose: The aim of this study was to confirm the validity of the $Cariview^{TM}$, test in adults by assessing correlations between $Cariview^{TM}$, scores and caries experience using a quantitative light-induced fluorescence (QLF) technique. Methods: This retrospective cross-sectional study included 111 patients aged 19-64 years who visited a dental clinic in Seoul from 2015 to 2016, and underwent the $Cariview^{TM}$, test and had their teeth photographed with the Qraycam. Plaque was scraped with sterilized cotton swabs, and then placed in a culture medium and incubated at $37^{\circ}C$ for 48 h. Finally, the degree of color change was evaluated, and scored on a 0-100 point scale. Caries experience index included not only cavitated lesions but also early caries that were detected on white and fluorescence images. Participants were divided into low, moderate and high caries risk groups according to the $Cariview^{TM}$, score, and caries experience was compared between risk groups using ANCOVA. Spearman correlation coefficients were calculated to analyze the associations between $Cariview^{TM}$, scores and caries indices. Result: The mean age of the participants was 40 years, and the mean $Cariview^{TM}$, score was $53.6{\pm}20.7$. The WDMFT and the DMFT indices significantly increased with caries risk, and this increase was significantly different between the low- and high-risk groups. The $Cariview^{TM}$, test scores were significantly correlated with the WDMFT (r = 0.28, P = 0.003) and DMFT (r = 0.29, P = 0.002) indices. Conclusion: The $Cariview^{TM}$, test could be a clinically useful and simple method for assessing caries risk in adults.