• 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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• 제40권3호
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• pp.135-141
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• 2015

Biofilms of oral microbes can cause various diseases in the oral cavity, such as dental caries, periodontitis and mucosal disease. Electrolyzed water generated by an electric current passed via water using a metal electrode has an antimicrobial effect on pathogenic bacteria which cause food poisoning. This study investigated the antimicrobial activity of electrolyzed waters using various metal electrodes on the floatage and biofilms of oral microbes. The electrolyzed water was generated by passing electric current using copper, silver and platinum electrodes. The electrolyzed water has a neutral pH. Streptococcus mutans, Porphyromonas gingivalis and Tannerella forsythia were cultured, and were used to form a biofilm using specific media. The floatage and biofilm of the microbes were then treated with the electrolyzed water. The electrolyzed water using platinum electrode (EWP) exhibited strong antimicrobial activity against the floatage and biofilm of the oral microbes. However, the electrolyzed water using copper and silver electrodes had no effect. The EWP disrupted the biofilm of oral microbes, except the S. mutans biofilm. Comparing the different electrolyzed waters that we created the platinum electrode generated water may be an ideal candidate for prevention of dental caries and periodontitis.

• 한국치위생학회지
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• 제21권5호
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• pp.555-565
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• 2021

Objectives: This study was conducted to analyze peri-implantitis bacteria and identify their associations with health status and health activities. Methods: Gingival sulcus fluid at the implant's periodontal pockets sampled from the participants were analyzed by multiplex real time PCR. Results: Participants had strains in the order of 100% F. nucleatum, 98.0% E. corrodens, and 96.0% P. micra, and the correlation between C. rectus and E. nodatum was high (p<0.01). Diabetic group (P. gingivalis, P. nigrescens) hypertension (P. nigrescens), group with four or more periodontal pockets (P. gingivalis, T. dentica, P. intermedia, E. nodatum, and C. rectum), smoking (P. micra, E. corrodens), drinking (T. dentola), and scaling groups (C. rectus) were found to have more strains (p<0.05). Conclusions: Representative pathogenic microorganisms detected in periodontal pockets of implants were similar to dental periodontal pockets; however there were differences in the amount and distribution of microorganisms, and they were affected by health status and health behavior.

• International Journal of Oral Biology
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• 제41권4호
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• pp.253-262
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• 2016

Streptococcus mutans (S. mutans) is one of the most important bacteria in the formation of dental plaque and dental caries. S. mutans adheres to an acquired pellicle formed on the tooth surface, and aggregates with many oral bacteria. It initiates plaque formation by synthesizing glucan from sucrose, which is catalyzed by glucosyltransferases. Propolis is a resinous mixture produced by honeybees, by mixing saliva and beeswax with secretions gathered from wood sap and flower pollen. Bees prevent pathogenic invasions by coating the propolis to the outer and inner surface of the honeycomb. Propolis has traditionally been used for the treatment of allergic rhinitis, asthma and dermatitis. We investigated the inhibitory effects of propolis ethanol extract on biofilm formation and gene expression of S. mutans. The biofilm formation of S. mutans was determined by scanning electron microscopy (SEM) and safranin staining. We observed that the extract of propolis had an inhibitory effect on the formation of S. mutans biofilms at concentrations higher than 0.2 mg/ml. Real-time PCR analysis showed that the gene expression of biofilm formation, such as gbpB, spaP, brpA, relA and vicR of S. mutans, was significantly decreased in a dose dependent manner. The ethanol extract of propolis showed concentration dependent growth inhibition of S. mutans, and significant inhibition of acid production at concentrations of 0.025, 0.05, 0.1 and 0.2 mg/ml, compared to the control group. These results suggest that the ethanol extract of propolis inhibits gene expression related to biofilm formation in S. mutans.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.31-40
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• 2008

Purpose: The probiotic effects of lactic acid bacteria have widely been researched in diverse human pathogens, but only a few effects are reported against oral pathogens. The antimicrobial effects of the Enterococcus faecium 7413 isolated from Korean infants on the 9 pathogen including 6 oral streptococci were investigated the clinical use of the antimicrobial peptide for oral microflora control. Materials and Methods: E. faecium 7413 was identified by morphological, biochemical tests and 16S rDNA sequence analysis. Inhibitory effects of culture supernatants were determined for their ability to grow on agar plate containing pathogenic bacteria. Result: The culture supernatant of Enterococcus faecium 7413 showed inhibitory effects on oral pathogens, namely Streptococcus pyogenes KCTC 3556, S. pneumoniae KCTC 5080, S. mutans ATCC 25175, S. anginosus ATCC 33397, S. constellatus KCTC 3268, S. intermedius ATCC 27823 and Shigella flexneri KCTC 2008. Whereas it did not affect the multiplication of E. coli strains, KCTC 1041 and ATCC 43894. Conclusion: The data obtained in this study could be useful for future development of effective probiotics allowing prevention for oral pathogens.

• Journal of Microbiology and Biotechnology
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• 제32권9호
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• pp.1186-1194
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• 2022

The intake of probiotic lactic acid bacteria not only promotes digestion through the microbiome regulated host intestinal metabolism but also improves diseases such as irritable bowel syndrome and inflammatory bowel disease, and suppresses pathogenic harmful bacteria. This investigation aimed to evaluate the immunomodulatory effects in intestinal epithelial cells and to study the clinical efficacy of the selected the Bifidobacterium breve and Bifidobacterium longum groups. The physiological and biochemical properties were characterized, and immunomodulatory activity was measured against pathogenic bacteria. In order to find out the mechanism of inflammatory action of the eight viable and sonicated Bifidobacterium spp., we tried to confirm the changes in the pro-inflammatory cytokines (TNF-α, interleukin (IL)-6, IL-12) and anti-inflammatory cytokine (IL-10), and chemokines, (monocyte chemoattractant protein-1, IL-8) and inflammatory enzymatic mediator (nitric oxide) against Enterococcus faecalis ATCC 29212 infection in Caco-2 cells and RAW 264.7 cells. The clinical efficacy of the selected B. breve and B. longum group was studied as a probiotic adjuvant for acute diarrhea in children by oral administration. The results showed significant immunomodulatory effects on the expression levels of TNF-α, IL-6, IL-12, MCP-1, IL-8 and NO, in sonicated Bifidobacterium extracts and viable bifidobacteria. Moreover, each of the Bifidobacterium strains was found to react more specifically to different cytokines. However, treatment with sonicated Bifidobacterium extracts showed a more significant effect compared to treatment with the viable bacteria. We suggest that probiotics functions should be subdivided according to individual characteristics, and that personalized probiotics should be designed to address individual applications.

• 한방안이비인후피부과학회지
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• 제17권3호
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• pp.26-32
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• 2004

Objective: The aim of this work is to investigate the antibacterial activity of the essential oil obtained from Artemisia lavandulaefolia (A. lavandulaefolia), as the development of microbial resistance to antibiotics make it essential to constantly look for new and active compounds effective against pathogenic bacteria. Method: The aerial parts of A. lavandulaefolia (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 were 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. Ninety-nine compounds accounting for 94.74$\%$<／TEX> of the oil were identified. The main compounds in the oil were 1,8-cineole (5.63$\%$), yomogi alcohol (4.49$\%$), camphor (4.92$\%$), a-caryophyllene (16.10$\%$), trans-a-famesene (5.09$\%$), a-terpineol (3.91$\%$), borneol (5.27$\%$), cis-chrysanthenol (6.98$\%$), and a-humulene oxide (3.33$\%$). The essential oil and its compounds were tested for antimicrobial activity against 10 different genera of oral bacteria. Conclusion: The essential oil of A. lavandulaefolia exhibited considerable inhibitory effects against all obligate anaerobic bacteria (MICs, 0.025 - 0.05 ㎎／ml) tested, while their major compounds demonstrated various degrees of growth inhibition

• 한국응용곤충학회지
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• 제48권3호
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• pp.385-392
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• 2009

Xenorhabdus nematophila (Xn)와 Photorhabdus tempeerata subsp. temperata (Ptt)의 곤충병원세균을 배추좀나방(Plutella xylostella)의 혈강에 주입할 경우 높은 병원력을 보였다. 본 연구는 이들 세균 배양액의 섭식 처리에 따른 배추좀나방에 대한 병원성 유기를 조사하였다. 세균 배양액만을 이용하여 배추좀나방 3령충에 섭식 처리한 결과 뚜렷한 병원성을 유발하지 못하였으나, Bacillus thurigiensis(Bt) 와 혼합 처리하였을 때 높은 Bt 병원성 제고 효과를 나타냈다. 물질 추적을 위해서 이 세균 배양액을 유기 용매를 이용하여 헥산, 에틸아세테이트 및 수용액 추출 분획구로 분리하였다. 대부분이 Bt 상승효과는 에틸아세테이트 추출 분획구에서 나타났다. Thin layer chromatography 분석 결과는 에틸아세테이트 분획구가 대사물질을 포함하고 있으며, 이들이 헥산 또는 수용액 추출 분획구에 포함된 물질과는 상이하다는 것을 나타냈다. 이러한 결과는 이들 곤충병원세균이 Bt 병원성을 제고시키는 물질을 생산하고 배양액으로 분비한다고 제시하고 있다.

• 한국어병학회지
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• 제27권2호
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• pp.107-114
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• 2014

세균성 어류질병의 치료 및 예방을 위하여 어류와 인체에 안전한 수산용 probiotic의 개발이 요구되고 있다. 본 연구에서는 남해안 일대에서 양식되고 있는 참굴 (Crassostrea gigas), 바지락 (Ruditapes philippinarum), 피조개 (Scapharca broughtonii), 새조개 (Fulvia mutica)의 가식 부위로부터 17균주의 candidate probiotic bacteria (CPB)를 분리하였다. 나아가 다양한 연쇄상구균 (Lactococcus garvieae, L. piscium, Streptococcus sp., S. iniae, and S. parauberis)에 대하여 강한 생장 억제력을 보이는 균주(CPB-St)를 선별하여 어류의 연쇄구균증 관리를 위한 probiotic 균주로서의 개발 가능성을 알아보았다. CPB-St 균주를 double layer test를 통하여 다양한 연쇄상구균들에 대한 생장 억제 정도를 알아보았으며, 혼합 배양에서의 Streptococcus sp.에 대한 생장 억제 능력을 확인하였고, CPB-St의 어류에 대한 안전성 및 장내 생존 유무를 평가하였다. CPB-St는 대부분의 연쇄상구균에 대하여 18~26 mm의 생장 억제대를 형성함으로써 높은 생장 억제 능력을 보였다. CPB-St와의 혼합 배양에서 Streptococcus sp.는 6시간째부터 생장 억제 현상이 관찰되기 시작하여 12시간 전후로 8~55배 정도의 감소를 나타내었다. CPB-St의 어류에 대한 병원성 유 무를 알아본 결과, 2주일 동안 CPB-St로 인한 어류 폐사는 관찰되지 않았다. CPB-St의 1회 강제 경구 투여 후, 위와 장에서 CPB-St의 생존을 확인한 결과 투여 24시간 후에는 CPB-St가 모두 배출되는 것으로 나타났다. CPB-St를 probiotic bacteria로 개발하기 위해서는 어류의 장내 정착 가능성과 먹이를 통한 효과의 정확한 검증이 추후 이루어져야 할 것이다.

• 기본간호학회지
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• 제13권3호
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• pp.351-358
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• 2006

Purpose: The purpose of this study was to compare the effects of oral hygiene with 0.1% chlorhexidine or with normal saline on the incidence of pathogens in the oral cavity of patients in Intensive Care Units (ICU). Method: A quasi experimental design with non-equivalent control group and non-synchronized design was used. For the study 46 patients were recruited from a university hospital (24 for the experimental group, 22 for the control group). patients in the experimental group received mouth care with 0.1% chlorhexidine gluconate and those in the control group received mouth care with normal saline twice a day for 7 days in a row. Oral samples were taken for bacterial cultures on admission day, the 4th day and the 7th day for both groups. Results: The incidence of oral pathogens decreased in the experimental group, and increased in the control group. There was no significant difference in the incidence of oral pathogens between the two groups. However oral hygiene using 0.1% chlorhexidine gluconate decreased the incidence of oral pathogens significantly for patients who already had pathogenic bacteria in their mouths on the admission day. Conclusion: The results suggest that mouth care with 0.1% chlorhexidine is effective for decreasing the incidence of oral infection for ICU patients who have oral infections.