• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.89-98
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• 1995

P. intermedia are considered an important pathogen in adult periodontitis, rapidly progressing periodontitis, refractory periodontitis, pregnancy gingivitis, acute necrotizing ulcerative gingivitis, pubertal gingivitis. So far 2 DNA homology groups and 3 serotypes of P. intermedia have been reported but there is no data available as yet regarding genetic diversity for the species P. intermedia. The purpose of this study is to investigate, using bacterial DNA restriction endonuclease analysis, genetic diversity between individual strains of P. intermedia which are indistinguishable by serotyping and biotyping, occurrence of an intrafamilial transmission and genetic heterogeneity between P. intermedia strains isolated within a patient and within the same serotypes. The families who have had no systemic disease, no experience of periodontal treatment for the previous 1 year and no experience of antibiotics for the previous 6 months were selected and subgingival plaque was collected at 4 sites in each person and incubated in the anaerobic chamber. P. intermedia were identified by colony shape, gram stain, biochemical test, SK-I03(Sunstar Inc.) test and IIF using monoclonal antibody was perfomed for the determination of serotypes. P. intermedia strains were grown in BHI broth and whole genomic DNA was extracted and digested by restriction endonuclease. The resulting DNA fragments were separated by agarose gel electrophoresis, stained and photographed under UV. As the results of this study, intrafamilial vertial transmissions could be assessed in 2 families and horizintal transmissions in another 2 families. There were different DNA digest patterns within a patient, so P. intermedia showed that individuals could be colonized by multiple clonal types at anyone time. And different serotypes could be found within a patient and in the same serotype within a patient, obvius genetic heterogeneity could not be assessed. But in the same serotype in different famies, there were differences in the DNA digest patterns.

• YAKHAK HOEJI
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• v.39 no.4
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• pp.417-426
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• 1995

6-[(N-4-Chlorophenyl)amino]-7-chloro-5,8-quinolinedione (RCK20) was tested for antifungal activities, in vivo, against Candida albicans. RCK20 was compared vath ketoconazole and fluconazole in the treatment of systemic infection with Candida albicans in normal rats. The therapeutic potential of RCK20 had been assessed by evaluating their activities (survival rate) against systemic infections with in normal mice with Candida albicans. RCK20 improved survival rates as well as ketokonazole. RCK20 had ED$_{50}$. 0.25$\pm$0.18 mg/kg but ketoeonazole and fluconazole had ED$_{50}$, 8.00$\pm$0.73, 10$\pm$0.43 mg/kg respectively. Activities of RCK20 showed superior to that of ketoconazole and fluconazole. Intraperitoneauy administered RCK20 at the ED$_{50}$, 0.25 mg/kg for 7days and 14days reduced Candida albicans colony count in the kidneys and livers as well as ketoconazole and fluconazole at these ED$_{50}$, 8.00 and 10 mg/kg. Acute oral toxicity studies of RCK20 were carried out in ICR mice of both sexes. These acute oral toxicities of RCK20 were low and LD$_{50}$ values were over 2.850 mg/kg in ICR mice. The Genotoxicities of RCK20 had been evaluated. RCK20 was negative in Ames test with Salmonella typhimurium (TA98 and TA100). The clastogenicity was tested on the RCK20 with in vivo mouse micronucleus assay. RCK20 did not show any clastogenic effect in mouse peripheral blood and was negative in mouse micronucleus assay. These results indicate that RCK20 has no genotoxic potential under these experimental condition.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.283-288
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• 1995

This study was carried out to investigate the toxic action of herbicide, paraquat(1,1'-dimethyl-4,4'-bipyridylium-dichloride), against microorganisms. The toxic effect of paraquat was observed mainly using Escherichia coli(KCTC 1039), as follows; Growth of aerobic microorganisms which comprise 4 strains of bacteria and 2 strains of yeast and 4 strains of mold was inhibited drastically in the presence of 1.0mM paraquat But the growth of anaerobic bacteria was not affected by the chemical. When actively growing cells of E. coli were exposed to the paraquat at the concentration higher than 1.0 mM, they rapidly lost their ability to form colony and clearly formed inhibitory zone by well test More than 50% of the cells were killed by 1.0 mM paraquat treatment, even at immediate addition of paraquat to the medium.

• YAKHAK HOEJI
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• v.22 no.1
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• pp.33-41
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• 1978

In order to study the growth and survival of enteric pathogens causing water-borne infections in sewage, the filter-sterilized and autoclaved sewages of Dae Gu City were inoculated with Salmonella typhimuriuim, Shigella flexneri 2a, Sh. sonnei I, Vibrio eltor and V. parahaemolyticus, as test series and Escherichia coli as control. After varying periods of incubation up to 15 days at $4^{\circ}$, $15^{\circ}$, $25^{\circ}$ and $37^{\circ}C$, viable cells in the inoculated sewages were counted by colony count technique. Distilled water and 0.9% saline were subjected to inoculation of the organisms was observed in the filter-sterilized and autoclaved sewages at $4^{\circ}$ and the sewages became sterile within a few days. At $15^{\circ}$, no growth and rapid inactivation of the organisms in the filter-sterilized sewage and slight or no growth in the autoclaved sewage was noted. Some viable cells were found in the autoclaved sewage after 15 days. A considerable growth was observed in the filter-sterilized and autoclayed sewages, at $25^{\circ}$ and $37^{\circ}$, and large numbers of viable cells were found even after 15days of incubation. In general, the autoclaved sewage supproted the growth more noticeably than the filter-sterilized, except for V.parahaemolyticus which grew well in filter-sterilized sewage. No marked difference was noted between incubations at $25^{\circ}$ and $37^{\circ}$, but V. parahaemolyticus showed a slightly more active growth at $25^{\circ}$ than at $37^{\circ}$. Distilled water inactivated the organisms within a few days, but saline supported the growth at $25^{\circ}$ and $37^{\circ}$. Marked differences were noted in the survival test of sewages pathogens of different origins.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.651-655
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• 2001

To investigate the antimutagenic effect of Platycodon grandiflorum DC, methanol extract of Platycodon grandiflorum DC was investigated. In Ames test, the methanol extract showed inhibitory effects of 80-90% on the mutagenicity induced by indirect mutagen of IQ(2-amino-3-methylimidazo[4,5-f]quinoline) and direct mutatgen of MNNG(N-methyl-N'-nitro-N-nitrosoguanidine) in Salmonella typhimurium TA 98 and TA 100. And then the methanol extract was further fractionated. Among the solvent extracted fractions from the methanol extract, the ethyl acetate fraction and butanol fraction exhibited the greatest antimutagenic effect suppressing the mutagenicity IQ and MNNG with inhibition rate of 99% and 98%.

• Restorative Dentistry and Endodontics
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• v.38 no.2
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• pp.65-72
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• 2013

Objectives: To evaluate the inhibitory effect of ursolic acid (UA)-containing composites on Streptococcus mutans (S. mutans) biofilm. Materials and Methods: Composite resins with five different concentrations (0.04, 0.1, 0.2, 0.5, and 1.0 wt%) of UA (U6753, Sigma Aldrich) were prepared, and their flexural strengths were measured according to ISO 4049. To evaluate the effect of carbohydrate source on biofilm formation, either glucose or sucrose was used as a nutrient source, and to investigate the effect of saliva treatment, the specimen were treated with either unstimulated whole saliva or phosphate-buffered saline (PBS). For biofilm assay, composite disks were transferred to S. mutans suspension and incubated for 24 hr. Afterwards, the specimens were rinsed with PBS and sonicated. The colony forming units (CFU) of the disrupted biofilm cultures were enumerated. For growth inhibition test, the composites were placed on a polystyrene well cluster, and S. mutans suspension was inoculated. The optical density at 600 nm ($OD_{600}$) was recorded by Infinite F200 pro apparatus (TECAN). One-way ANOVA and two-way ANOVA followed by Bonferroni correction were used for the data analyses. Results: The flexural strength values did not show significant difference at any concentration (p > 0.01). In biofilm assay, the CFU score decreased as the concentration of UA increased. The influence of saliva pretreatment was conflicting. The sucrose groups exhibited higher CFU score than glucose group (p < 0.05). In bacterial growth inhibition test, all experimental groups containing UA resulted in complete inhibition. Conclusions: Within the limitations of the experiments, UA included in the composite showed inhibitory effect on S. mutans biofilm formation and growth.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.1-6
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• 2013

Tetanus is a specific infectious disease, which is often associated with catastrophic events such as earthquakes, traumas, and war wounds. The obligate anaerobe Clostridium tetani is the pathogen that causes tetanus. Once the infection of tetanus progresses to an advanced stage within the wounds of limbs, the rates of amputation and mortality increase manifold. Therefore, it is necessary to devise a rapid and sensitive point-of-care detection method for C. tetani so as to ensure an early diagnosis and clinical treatment of tetanus. In this study, we developed a detection method for C. tetani using loop-mediated isothermal amplification (LAMP) assay, wherein the C. tetani tetanus toxin gene was used as the target gene. The method was highly specific and sensitive, with a detection limit of 10 colony forming units (CFU)/ml, and allowed quantitative analysis. While detecting C. tetani in clinical samples, it was found that the LAMP results completely agreed with those of the traditional API 20A anaerobic bacteria identification test. As compared with the traditional API test and PCR assay, LAMP detection of C. tetani is simple and rapid, and the results can be identified through naked-eye observation. Therefore, it is an ideal and rapid point-of-care testing method for tetanus.

• Journal of Korean Academy of Dental Administration
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• v.7 no.1
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• pp.50-55
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• 2019

The purpose of this study was to compare the number of bacteria before and after the use of surface disinfectants, demonstrate the bactericidal effect of surface disinfectants, and emphasize on the importance of surface disinfectants by recognizing the importance of infection control in dentistry. Chlorhexidine, hydrogen peroxide, ethanol, and chemical disinfectants are commonly used in dentistry. NaOCl was selected as the experimental group, and the bacterium test results obtained by comparing the table without surface sterilization as a control group showed that all disinfectants had an effective bactericidal effect (p<0.05). In the growth inhibition test comparing the experimental and control groups, all results were 100%, proving the effectiveness of surface disinfectants. The results showed that all surface disinfectants preferred and used by medical institutions were effective. Therefore, all surface disinfectants used in the experimental group were effective for surface disinfection for infection control. Dental clinicians should be aware of the necessity of disinfection of surfaces, such as table, chairs, and unit chairs, and make an active effort to ensure that both clinicians and patients are safe from infection.

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.20.1-20.11
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• 2021

Objectives: The aim of this study was to evaluate bacterial nanocellulose (BNC) membranes incorporated with antimicrobial agents regarding cytotoxicity in fibroblasts of the periodontal ligament (PDLF), antimicrobial activity, and inhibition of multispecies biofilm formation. Materials and Methods: The tested BNC membranes were BNC + 1% clindamycin (BNC/CLI); BNC + 0.12% chlorhexidine (BNC/CHX); BNC + nitric oxide (BNC/NO); and conventional BNC (BNC; control). After PDLF culture, the BNC membranes were positioned in the wells and maintained for 24 hours. Cell viability was then evaluated using the MTS calorimetric test. Antimicrobial activity against Enterococcus faecalis, Actinomyces naeslundii, and Streptococcus sanguinis (S. sanguinis) was evaluated using the agar diffusion test. To assess the antibiofilm activity, BNC membranes were exposed for 24 hours to the mixed culture. After sonicating the BNC membranes to remove the remaining biofilm and plating the suspension on agar, the number of colony-forming units (CFU)/mL was determined. Data were analyzed by 1-way analysis of variance and the Tukey, Kruskal-Wallis, and Dunn tests (α = 5%). Results: PDLF metabolic activity after contact with BNC/CHX, BNC/CLI, and BNC/NO was 35%, 61% and 97%, respectively, compared to BNC. BNC/NO showed biocompatibility similar to that of BNC (p = 0.78). BNC/CLI showed the largest inhibition halos, and was superior to the other BNC membranes against S. sanguinis (p < 0.05). The experimental BNC membranes inhibited biofilm formation, with about a 3-fold log CFU reduction compared to BNC (p < 0.05). Conclusions: BNC/NO showed excellent biocompatibility and inhibited multispecies biofilm formation, similarly to BNC/CLI and BNC/CHX.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.10-21
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• 2015

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 $Dentocult^{(R)}$-SM strip mutans, polymerase chain reaction was performed to test whether Streptococcus mutans and Streptococcus sobrinus were present, and Streptococcus mutans detecting tests performed in their saliva using four types of monoclonal antibody were collected. In conclusion, it was demonstrated that the Streptococcus mutants plays more important role in forming dental caries compared to Streptococcus sobrinus, and that the monoclonal antibodies against glucosyltransferases (gtf B, gtf C, gtf D) and Ag I/II of Streptococcus mutans are superior in detecting Streptococcus mutans to $Dentocult^{(R)}$-SM strip mutans or polymerase chain reaction.