• International Journal of Oral Biology
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• 제40권2호
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• pp.79-83
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• 2015

The purpose of the study was to investigate the antimicrobial activity of the methanol extract of Coptidis rhizome against the type strains of cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, and the periodontopathogens, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extract and the methanol extract fractions of Coptidis rhizome separated by silica gel chromatography were evaluated by determining the minimal bactericidal concentration (MBC) values, using the microdilution method. The cell viability test of the extracts of Coptidis rhizome on the KB cells was also studied by methyl thiazolyl tetrazolium (MTT) assay. Our results showed that the 11th fraction (F11) of the methanol extract had the greatest antimicrobial activity against the tested bacteria, with no associated cytotoxicity on the KB cells, upto a concentration of $50{\mu}g/ml$. These results suggest that the silica gel chromatography fraction F11 of the methanol extract of Coptidis rhizome, could be useful in the development of oral hygiene products as an antimicrobial agent for the prevention of dental caries and periodontal diseases.

• 보건의료생명과학 논문지
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• 제11권2호
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• pp.393-405
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• 2023

구강질환은 전 세계적으로 약 35억 명의 인구에 영향을 미치는 것으로 보고되었고, 국내에서 치은염 및 치주질환이 2019년부터 2021년까지 다빈도 상병 1위를 차지하였다. 구강질환을 일으키는 대표적인 박테리아로 Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus gordonii, Leptotrichia buccalis, Prevotella, Treponema 등이 있고, 진균류로는 Candida albicans, 고세균으로 Methanobrevibacter oralis 등이 있다. 구강 미생물이 치주질환을 일으키는 과정을 살펴보면, Streptococcus mutans 와 같은 박테리아가 먼저 증식하여 바이오필름을 형성하고, 이어서 절대혐기성 미생물, 기회감염균 및 병원균이 부착하여 증식하면서 숙주의 치은연하에 치태를 형성하며 정착하게 된다. 이처럼 마이크로바이옴 군집 내 다양한 상호작용이 구강질환 발생에 중요하다. 나아가서 구강 미생물과 구강질환으로 인하여 생성된 물질 및 염증이 소화기질환, 당뇨병, 심혈관질환, 인지기능, 류마티스 관절염, 조산, 암과 같은 질환 발생과 밀접한 관련성이 있으며, 한편으로 이러한 질환들이 구강질환을 일으키는 원인이 된다.

• 한국치위생학회지
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• 제17권1호
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• pp.13-25
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• 2017

Objectives: The purpose of this study was to compare colony forming unit (CFU) method and multiplex real-time polymerase chain reaction (MRT-PCR) method for accurate quantitative analysis of bacteria. Methods: We compared the CFU method and the MRT-PCR method, which are still used in Korea, for Prevotella intermedius (P. intermedius), a periodontal disease pathogen selected by MRT-PCR, and Streptococcus mutans (S. mutans), a dental caries causative organism. The subjects of this study were 30 patients who visited the C dental hospital. Results: Total microorganisms in MRT-PCR method were significantly higher in both types of bacteria (p<0.05), since DNA of dead bacteria was also analyzed. This was because the periodontal dise(-) anaerobes, and even dead bacteria contain large amounts of toxic substances called LPS in the extracellular membrane, and fimbriae and pili, which are motility structures, still remain as a strong toxic substance in periodontal tissue. Conclusions: Therefore, in terms of the total amount of bacteria found, the MRT-PCR method will be a useful technique for searching all the bacteria in the oral cavity including live bacteria, as well as sterilization.

• 대한한의학회지
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• 제25권4호
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• pp.121-128
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• 2004

Objective : The aim of this work is to investigate the antibacterial activity of the essential oil obtained from Artemisia capillaris (A. capillaris), as the development of microbial resistance to antibiotics make it necessary to constantly look for new and active compounds effective against pathogenic bacteria. Methods : The crushed materials of A. capillaris (1 kg) were subjected to steam distillation for 3 h, using a modified Clevenger type apparatus in order to obtain essential oil. Diethyl ether was the extracting solvent kept at 25°.... The essential oil was analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The essential oil and the composition were tested for antimicrobial activities against 15 different genera of oral bacteria. Results and Conclusion : The components of the essential oil identified were: β-pinene (9.36%), camphor (3.32%), 1,8­cineole (4.38%), artemisia alcohol (3.32%), β-caryophyllene (11.08%), γ-cadinene (4.23%), and capillene (32.74%). The essential oil of A. capillaris exhibited considerable inhibitory effects against all oral bacteria tested, while their major components demonstrated various degrees of growth inhibition.

• 치위생과학회지
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• 제19권2호
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• pp.86-95
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• 2019

The modern era of microbial genome analysis began in earnest in the 2000s with the generalization of metagenomics and gene sequencing techniques. Studying complex microbial community such as oral cavity and colon by a pure culture is considerably ineffective in terms of cost and time. Therefore, various techniques for genomic analysis have been developed to overcome the limitation of the culture method and to explore microbial communities existing in the natural environment at the gene level. Among these, DNA fingerprinting analysis and microarray chip have been used extensively; however, the most recent method of analysis is metagenomics. The study summarily examined the overview of metagenomics analysis techniques, as well as domestic and foreign studies on disease genomics and cluster analysis related to oral metagenome. The composition of oral bacteria also varies across different individuals, and it would become possible to analyze what change occurs in the human body depending on the activity of bacteria living in the oral cavity and what causality it has with diseases. Identification, isolation, metabolism, and presence of functional genes of microorganisms are being identified for correlation analysis based on oral microbial genome sequencing. For precise diagnosis and treatment of diseases based on microbiome, greater effort is needed for finding not only the causative microorganisms, but also indicators at gene level. Up to now, oral microbial studies have mostly involved metagenomics, but if metatranscriptomic, metaproteomic, and metabolomic approaches can be taken together for assessment of microbial genes and proteins that are expressed under specific conditions, then doing so can be more helpful for gaining comprehensive understanding.

• International Journal of Oral Biology
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• 제39권4호
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• pp.207-213
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• 2014

Antimicrobial actions of reactive oxygen/nitrogen species (ROS/RNS) derived from products of NADPH oxidase and inducible nitric oxide (NO) synthase in host phagocytes inactivate various bacterial macromolecules. To cope with these cytotoxic radicals, pathogenic bacteria have evolved to conserve systems necessary for detoxifying ROS/RNS and repairing damages caused by their actions. In response to these stresses, bacteria also induce expression of molecular chaperones to aid in ameliorating protein misfolding. In this study, we explored the function of a newly identified chaperone Spy, that is localized exclusively in the periplasm when bacteria exposed to conditions causing spheroplast formation, in the resistance of Salmonella Typhimurium to ROS/RNS. A spy deletion mutant was constructed in S. Typhimurium by a PCR-mediated method of one-step gene inactivation with ${\lambda}$ Red recombinase, and subjected to ROS/RNS stresses. The spy mutant Salmonella showed a modest decrease in growth rate in NO-producing cultures, and no detectable difference of growth rate in $H_2O_2$ containing cultures, compared with that of wild type Salmonella. Quantitative RT-PCR analysis showed that spy mRNA levels were similar regardless of both stresses, but were increased considerably in Salmonella mutants lacking the flavohemoglobin Hmp, which are incapable of NO detoxification, and lacking an alternative sigma factor RpoS, conferring hypersusceptibility to $H_2O_2$. Results demonstrate that Spy expression can be induced under extreme conditions of both stresses, and suggest that the protein may have supportive roles in maintaining proteostasis in the periplasm where various chaperones may act in concert with Spy, thereby protecting bacteria against toxicities of ROS/RNS.

• International Journal of Oral Biology
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• 제30권2호
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• pp.65-69
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• 2005

Periodontitis is a multi-microbial disease and the comparison of a series of periodontopathogenic and non-periodontopathogenic bacteria in terms of microbe-host interaction may provide clues to understand the microbial etiology of the disease better. When we deal with twenty different bacterial species in a study, the first technical issue is how to measure the accurate concentration and use the same number of bacterial cells. We measured bacterial concentration by enumerating bacteria stained with SYTOX green for constant time using a flow cytometer and compared the results with those obtained by plate counting. Concentrations calculated by two different methods were very close. Therefore, flow cytometric counting allowed the rapid analysis of live/dead bacteria, offering the advantage of turbidity measurement and that of colony counting together.

• Journal of Periodontal and Implant Science
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• 제43권1호
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• pp.3-11
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• 2013

Periodontitis is a chronic inflammation of periodontal tissue caused by subgingival plaque-associated bacteria. Periodontitis has long been understood to be the result of an excessive host response to plaque bacteria. In addition, periodontal pathogens have been regarded as the causative agents that induce a hyperinflammatory response from the host. In this brief review, host-microbe interaction of nonperiodontopathic versus periodontopathic bacteria with innate immune components encountered in the gingival sulcus will be described. In particular, we will describe the susceptibility of these microbes to antimicrobial peptides (AMPs) and phagocytosis by neutrophils, the induction of tissue-destructive mediators from neutrophils, the induction of AMPs and interleukin (IL)-8 from gingival epithelial cells, and the pattern recognition receptors that mediate the regulation of AMPs and IL-8 in gingival epithelial cells. This review indicates that true periodontal pathogens are poor activators/suppressors of a host immune response, and they evade host defense mechanisms.

• 약학회지
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• 제30권1호
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• pp.8-13
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• 1986

It has been assumed that nitrite, one of the precursor of N-nitrosamine, in human saliva must have been formed from salivary nitrate through the action of microorganism in the oral cavity. In this paper, we have tested the concentration of nitrite and nitrate in human saliva and the degrees of nitrate reduction by oral microflora and identified some bacteria which were able to reduce nitrate. The concentration of nitrite and nitrate was 1.7~9.5ppm and 9.0~28.5ppm respectively. The numbers of total bacteria and nitrate reducing bacteria in four korean human saliva sample were 15~63${\times}10^8$ CFU and 1.0~6.0${\times}10^8$ CFU and the main nitrate reducing bacteria were Streptococcus uberis which was presented in large quantities and showed remarkable reductive activity. Lastly, we knowed that N-dimethylnitrosamine was formed by the reaction between dimethylamine and nitrite in the presence of St. uberis in vitro.

• 한국산학기술학회논문지
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• 제17권6호
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• pp.537-545
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• 2016

본 연구는 구강환경요인을 살펴보고, 구강환경이 구강세균 검출에 미치는 위험요인 알아보고자 시행하였다. 연구기간은 2015년 2월 15일~ 2월 28일까지 성인 근로자 60명을 대상으로 조사하였다. 연구변수로는 안정시, 자극시 타액분비율, 타액완충능, 타액 pH, 설배와 설하 구강건조도, 구취 설태량을 측정하였다. 구강세균의 검출 유무를 확인하기 위하여 안정시 타액분비율의 gDNA를 추출하여 균을 검출하였다. 그 결과, S.mutans균은 흡연자 15배, 자극시, 안정시 타액분비율 1.3~1.6배 위험도가 더 높았으며, P.intermedia는 흡연자 13배, 설하 구강건조도 4.3배, 설태량 4배 TM7은 설하 구강건조도 5.5배 더 높은 위험도를 나타냈다. 구강 내 세균을 줄이기 위해서는 타액분비율을 촉진시키는 습관을 형성하고, 금연교육을 시행함이 중요하다고 본다. 또한 구강위생이 깨끗하고 관리가 잘되는 성인에서는 구강세균이 많이 줄어들고, 구강질환을 좀 더 예방할 수 있을 것이라 기대된다.