• Restorative Dentistry and Endodontics
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• 제38권1호
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• pp.36-42
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• 2013

Objectives: This study evaluated the antibacterial effect and mechanical properties of composite resins ($L_{CR}$, $M_{CR}$, $H_{CR}$) incorporating chitosan with three different molecular weights (L, Low; M, Medium; H, High). Materials and Methods: Streptococcus (S). mutans 100 mL and each chitosan powder were inoculated in sterilized 10 mL Brain-Heart Infusion (BHI) solution, and was centrifuged for 12 hr. Absorbance of the supernatent was measured at $OD_{660}$ to estimate the antibacterial activities of chitosan. After S. mutans was inoculated in the disc shaped chitosan-containing composite resins, the disc was cleansed with BHI and diluted with serial dilution method. S. mutans was spread on Mitis-salivarius bacitracin agar. After then, colony forming unit (CFU) was measured to verify the inhibitory effect on S. mutans biofilm. To ascertain the effect on the mechanical properties of composite resin, 3-point bending and Vickers hardness tests were done after 1 and 3 wk water storage, respectively. Using 2-way analysis of variance (ANOVA) and Scheffe test, statistical analysis was done with 95% significance level. Results: All chitosan powder showed inhibition effect against S. mutans. CFU number in chitosan-containing composite resins was smaller than that of control resin without chitosan. The chitosan containing composite resins did not show any significant difference in flexural strength and Vickers hardness in comparison with the control resin. However, the composite resin, $M_{CR}$ showed a slightly decreased flexural strength and the maximum load than those of control and the other composite resins $H_{CR}$ and $L_{CR}$. Conclusions: $L_{CR}$ and $H_{CR}$ would be recommended as a feasible antibacterial restorative due to its antibacterial nature and mechanical properties.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.748-756
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• 2016

In the present study, a lipopeptide (named AXLP14) antagonistic to Xanthomonas oryzae pv. oryzae (Xoo) was obtained from the culture supernatant of Bacillus amyloliquefaciens B014. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis demonstrated that AXLP14 consisted of surfactin homologs. The minimum inhibition concentration and minimum bactericidal concentration of AXLP14 against Xoo were determined to be 1.25 and 2.50 mg/ml, respectively. At a concentration of 0.613 mg/ml, AXLP14 strongly inhibited the formation of Xoo biofilm. AXLP14 also inhibited the motility of Xoo in a concentration-dependent manner. Applying AXLP14 to rice seedlings significantly reduced the incidence and severity of disease caused by Xoo. In Xoo-infected rice seedlings, AXLP14 strongly and continuously up-regulated the expression of both OsNPR1 and OsWRKY45. In addition, AXLP14 effectively inhibited the Xoo-induced up-regulation of the expression of the abscisic acid biosynthesis gene OsNECD3 and the abscisic acid signalingresponsive gene OsLip9, indicating that AXLP14 may protect rice against Xoo-induced disease by enhancing salicylic acid defense and interfering with the abscisic acid response to virulence.

• KSBB Journal
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• 제30권2호
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• pp.69-76
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• 2015

The antibacterial activity of a antimicrobial (organic synthetic or organic natural material) on the bacteria (Bacillus megaterium, Arthrobacter oxydans, Micrococcus luteus, Methylobacterium aquaticum) detected in the automobiles showed 99.9% bacteria decrease rate within 30 min of being in contact with the tested bacteria culture. The MIC of the organic synthetic material based antimicrobials and the organic natural material based antimicrobial on the bacteria were 31~500 mg/mL and 8~250 mg/mL, respectively. The bacteria and biofilms were formed on the surface of aluminum after 5 ~8 days in the case of addition of the organic synthetic material based antimicrobial to the MIC values for the tested bacteria culture. On the other hand, there was no proliferation of bacteria and formation of biofilms on the surface of aluminum even after 30 days in the case of addition of the organic natural material based antimicrobial to the MIC values for the tested bacteria culture. As a result, the organic natural material based antimicrobial was confirmed to be more excellent effect of inhibition of bacterial proliferation and restraint of biofilms formation than the organic synthetic material based antimicrobial.

• The Plant Pathology Journal
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• 제35권5호
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• pp.425-436
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• 2019

Botrytis cinerea, a major phytopathogenic fungus, has been reported to infect more than 200 crop species worldwide, and it causes massive losses in yield. The aim of this study was to evaluate the inhibitory abilities and effects of Bacillus amyloliquefaciens RS-25, Bacillus licheniformis MG-4, Bacillus subtilis Z-14, and Bacillus subtilis Pnf-4 and their culture filtrates and extracts against the gray mold caused by B. cinerea on postharvest tomato, strawberry, and grapefruit. The results revealed that the cells of Z-14, culture filtrate of RS-25, and cells of Z-14 showed the strongest biocontrol activity against the gray mold on the strawberry, grape, and tomato fruit, respectively. All the strains produced volatile organic compounds (VOCs), and the VOCs of Pnf-4 displayed the highest inhibition values. Based on headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry, esters accounted for the largest percentage of the VOCs produced by RS-25, MG-4, Z-14, and Pnf-4 (36.80%, 29.58%, 30.78%, and 36.26%, respectively). All the strains showed potent cellulase and protease activities, but no chitinase activity. RS-25, Z-14, and MG-4, but not Pnf-4, grew on chrome azurol S agar, and an orange halo was formed around the colonies. All the strains showed biofilm formation, fruit colonization, and lipopeptide production, which may be the main modes of action of the antagonists against B. cinerea on the fruit. This study provides the basis for developing natural biocontrol agents against the gray mold caused by B. cinerea on postharvest fruit.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1315-1324
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• 2022

Fermentation is an effective process for providing various beneficial effects in functional beverages. Lactic acid bacteria and yeast fermentation-based biotransformation contribute to enhancement of nutritional value and digestibility, including lactose intolerance reduction and control of infections. In this study, the probiotic fermented fruit juice (PFJ) was produced by Lactobacillus plantarum TISTR 1465, Lactobacillus salivarius TISTR 1112, and Saccharomyces boulardii CNCM I-745 while mixed fruit juice (MFJ) was used as the basic medium for microorganism growth. The potential function, the anti-salmonella activity of PFJ, was found to be effective at 250 mg/ml of MIC and 500 mg/ml of MBC. Biofilm inhibition was performed using the PFJ samples and showed at least 70% reduction in cell attachment at the MIC concentration of Salmonella Typhi DMST 22842. The antioxidant activities of PFJ were determined and the results revealed that FSB.25 exhibited 78.40 ± 0.51 mM TE/ml by FRAP assay, while FPSB.25 exhibited 3.44 ± 0.10 mM TE/ml by DPPH assay. The volatile compounds of PFJ were characterized by GC-MS, which identified alcohol, aldehyde, acid, ester, ketone, phenol, and terpene. The most abundant organic acid and alcohol detected in PFJ were acetic acid and 2-phenylethanol, and the most represented terpene was β-damascenone. The sensory attributes showed scores higher than 7 on a 9-point hedonic scale for the FPB.25, illustrating that it was well accepted by panelists. Taken together, our results showed that PFJ could meet current consumer demand regarding natural and functional, fruit-based fermented beverages.

• 대한치과교정학회지
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• 제53권1호
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• pp.16-25
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• 2023

Objective: We aimed to evaluate the cell viability and antimicrobial effects of orthodontic bands coated with silver or zinc oxide nanoparticles (nano-Ag and nano-ZnO, respectively). Methods: In this experimental study, 30 orthodontic bands were divided into three groups (n = 10 each): control (uncoated band), Ag (silver-coated band), and ZnO (zinc oxide-coated band). The electrostatic spray-assisted vapor deposition method was used to coat orthodontic bands with nano-Ag or nano-ZnO. The biofilm inhibition test was used to assess the antimicrobial effectiveness of nano-Ag and nano-ZnO against Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Biocompatibility tests were conducted using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The groups were compared using oneway analysis of variance with a post-hoc test. Results: The Ag group showed a significantly higher reduction in the number of L. acidophilus, C. albicans, and S. mutans colonies than the ZnO group (p = 0.015, 0.003, and 0.005, respectively). Compared with the control group, the Ag group showed a 2-log₁₀ reduction in all the microorganisms' replication ability, but only S. mutants showed a 2-log₁₀ reduction in replication ability in the ZnO group. The lowest mean cell viability was observed in the Ag group, but the difference between the groups was insignificant (p > 0.05). Conclusions: Coating orthodontic bands with nano-ZnO or nano-Ag induced antimicrobial effects against oral pathogens. Among the nanoparticles, nano-Ag showed the best antimicrobial activity and nano-ZnO showed the highest biocompatibility.

• 대한본초학회지
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• 제30권6호
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• pp.55-61
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• 2015

Objectives : Yongdamgosam-hwan(YGH) has been used as a traditional medicine from old times for antiinflammatory effects. Streptococcus mutans(S. mutans) is known as a prime bacteria responsible for causing caries by forming a biofilm referred to as dental plaque on the tooth surface. But antimicrobial activity of YGH with dental disease is not sufficiently understood. This study was designed to investigate the effects of YGH ethanol extract on antimicrobial effect against Streptococcus mutans.Methods : The antimicrobial effect of YGH ethanol extract was assessed by the paper disk diffusion method and optical density method to determine minimum inhibition concentration(MIC), also observed by fractional inhibitory concentration index(FICI) and time-kill assay to figure out the synergic effect on the combination of YGH ethanol extract with antibiotics.Results : The YGH ethanol extract 500 μg was 7.5-8.5 mm diameter of clear zone of inhibition against Streptococcus mutans in a concentration-dependent manner and MIC was 250 μg/mL. The administration of the ethanol extract in combination with gentamicin and streptomycin induced a reduction of ≥4-8-fold in all tested bacteria. Furthermore, time-kill study was found that a combination of YGH ethanol extract with oxacillin and streptomycin produced a more rapid decrease in the concentration of bacteria CFU/mL than the YGH ethanol extract or antibiotics alone.Conclusions : As a result, the YGH ethanol extract has good antimicrobial effects. And the results suggest that YGH could be employed as a natural antibacterial agent in dental care products.

• 상하수도학회지
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• 제24권4호
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• pp.433-442
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• 2010

BER at different packing ratios of bio-ring media(BRM) was tested to investigate the effect of varying hydraulic retention time (HRT) and current density on the nitrate removal and current efficiency. In the preliminary batch mode experiment of BERs, current density was applied at 2.0 A/$m^2$, 4.0 A/$m^2$, 4.8 A/$m^2$, which correspond to the designation of reactor #1, #2, #3, respectively. The reactor #2 showed a highest nitrate removal rate of 162.0 mg $NO_3{^-}$-N/L/d, and the kinetics of nitrate removal rate was defined as the Zero order reaction. In the primary experiment of BERs, four BERs packed with BRM were operated in varying HRT and current, and the packing ratios of reactor #1, #2, #3 and #4 were 0%, 8%, 16%, 24%. respectively. This results of the experiments indicated that the nitrate removal rate and current efficiency were increased significantly cause of growing of autotrophic denitrification microorganisms on the surface of cathode and media by increasing of the current density and decreasing of HRT. However, The decreasing of nitrate removal rate and current efficiencies were observed in the condition of HRT of 5.25 hr and 4.8 A/$m^2$ of current density. With more increasing current density and decreasing of HRT, the hydrogen inhibition occurred at the surface of cathode. Moreover, nitrate removal rate by autotrophic denitrification microorganisms attached on the media surface was observed to be limited by no longer increasing dissolved hydrogen concentration of each reactor. In conclusion, the highest nitrate nitrogen removal and current efficiency could be achieved when the BER was operated at the conditions of 7 hr HRT, current density of 4.0 A/$m^2$, and 16% packing ratio. And it was found that the amount of nitrate removal by microorganisms attached on the surface of cathode and media (BRM) was 178.2 mg/L and 52.2 mg/L respectively. and the amount of nitrate removal per MLVSS was 0.435 g $NO_3{^-}$-N/g $MLVSS{\cdot}d$ and 0.336 $NO_3{^-}$-N/g $MLVSS{\cdot}d$.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.3-3
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• 2018

For centuries, Panax ginseng Meyer (Korean ginseng) has been widely used as a medicinal herb in Korea, China, and Japan. Ginsenosides are a class of triterpene saponins and recognized as the bioactive components in Korean ginseng. Ginsenosides, which can be classified broadly as protopanaxadiols (PPD), protopanaxatriols (PPT), and oleanolic acids, have been shown to flaunt a vast array of pharmacological activities such as immune-modulatory, anti-inflammatory, anti-tumor, anti-diabetic, and antioxidant effects. In recent years, a number of ginseng and ginsenoside researches have increasingly gained wide attention owing to its unique pharmacological properties. Although good efficacies of ginsenosides have been reported, lack of target specific delivery into tumor sites, low solubility, and low bioavailability due to modifications in gastro-intestinal environments limit their biomedical application in clinical trials. As a result to this major challenge, nanotechnology and drug delivery techniques play a significant role to solve this problematic issue. Thus, we reported the preparation of poly-ethylene glycol (PEG) and glycol chitosan (GC) functionalized to ginsenoside (Compound K and PPD) conjugates via hydrolysable ester bonds with improved aqueous solubility and pH-dependent drug release. In vitro cytotoxicity assays revealed that PEG-CK, and PPD-CK conjugates exhibited lower cytotoxicity compared to bare CK and PPD in HT29 cells. However, GC-CK conjugates exhibited higher and similar cytotoxicity in HT29 and HepG2 cells. Furthermore, GC-CK-treated RAW264.7 cells did not exhibit significant cell death at higher concentration of treatment which supports the biocompatibility of the polymer conjugates. They also inhibited nitric oxide production in lipopolysaccharide (LPS)-induced RAW64.7 cells. In addition to polymer-ginsenoside conjugates, silver (AgNps) and gold nanoparticles (AuNps) have been successfully synthesized by green chemistry using different m. The biosynthesized nanoparticles demonstrated antimicrobial efficacy, anticancer, anti-inflammatory, antioxidant activity, biofilm inhibition, and anticoagulant effect. Special interest on the effective delivery methods of ginsenoside to treatment sites is the focus of metal nanoparticle research.In short, nano-sizing of ginsenoside results in an increased water solubility and bioavailability. The use of nano-sized ginsenoside and P. ginseng mediated metallic nanoparticles is expected to be effective on medical platform against various diseases in the future.

• KSBB Journal
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• 제20권4호
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• pp.253-259
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• 2005

본 연구는 고정 생물막을 이용한 혐기/무산소/호기 공정으로 구성된 반응기에서 폴리에틸렌 재질의 표면을 이온빔으로 조사하여 소수성 표면을 친수성으로 만든 표면개질담체를 호기조의 여재로 사용하고 혐기/무산소조의 여재로는 표면 개질을 하지 않은 담체를 사용하여, 외부 탄소원 대신 원수내의 RBDCOD를 탄소원으로 이용하고자 혐기조와 무산소조에 원수를 분할 주입하였을 때 나타나는 유기물 및 T-N 제거 특성을 알아보았다. 혐기/무산소조로의 원수 분배율이 각각 10 : 0, 9 : 1, 8 : 2, 6 : 4로 설정하였으며, 각각의 분배율에 대하여 $93.3\%,\;92.6\%,\;92.4\%,\;91.6\%$의 $BOD_5$ 제거율 (유기물의 제거능)을 보였다. 하지만 무산소조까지의 $BOD_5$ 제거율(유기물 이용능)은 9 : 1에서 $84.8\%$로 가장 높은 것으로 나타났으며, 분배율 10 : 0, 8 : 2는 각각 $77.0\%,\;75.3\%$로서 거의 비슷한 수준이었고, 분배율 6 : 4 경우에 $61.1\%$로 가장 낮은 수치를 나타내었다. T-N 제거율은 9 : 1의 분배율로 분할하였을 때가 $67.4\%$로 가장 제거 효율이 높았으며, 분배율 10 : 0, 8 : 2 경우는 각각 $61.3\%,\;60.7\%$로 비슷한 경향을 보였으나 분배율을 6 : 4로 하였을 때는 $55.5\%$의 제거율을 나타내 분배율 9 : 1의 경우와는 약 $12\%$의 차이를 보였다. 또한 10 : 0, 9 : 1, 8 : 2의 분배율에서는 질산화가 거의 비슷한 수준으로 발생하였지만, 6 : 4로 주입하였을 경우에는 질산화의 저해가 나타나고, 방류수 중의 대부분의 질소성분이 암모니아 성분으로 방류되었다. 이 공정에서 탄소원으로 생하수를 이용하는 것이 메탄올과 같은 독성 탄소원에 비해 독성을 지니지 않고 약품비용이 들지 않는다는 측면에서 유리할 것으로 사료된다.