• 대한치과보철학회지
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• 제56권4호
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• pp.391-395
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• 2018

진료실에서 지르코니아의 수요가 증가하고 있음에 따라 지르코니아의 생체적합성에 대한 평가가 필수적이다. 이번 논문에서는 지르코니아의 생체적 합성에 대한 문헌 중 in vitro 실험에서의 결과를 고찰하였다. Fibroblast, osteoblast, lymphocyte 등 다양한 세포를 이용한 in vitro 실험에서 지르코니아 블록은 뛰어난 생체적합성을 보였다. 여러 연구에서 지르코니아에 대한 세포독성 및 돌연변이 유발이 관찰되지 않았으며, 세균부착도 적은 것으로 나타났다. 장기간 체액노출조건을 모방한 in vitro 실험에서는 약간의 기계적 강도의 감소 외에는 악영향이 관찰되지 않았다. Osteoblast-like cell을 이용한 연구에서, 지르코니아 블록이 면역반응, 물질이동, 세포주기조절에 관여하는 유전자를 조절하여 생체적합을 높이는 것으로 관찰되었다. 여러 in vitro 연구에서 지르코니아 분말의 생체적합성에 대해서는 상이한 보고가 나타나고 있다. 종합적으로 지르코니아 분말은 어느 정도 세포독성을 가지고 있는 것으로 생각된다.

• 대한의생명과학회지
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• 제9권4호
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• pp.195-201
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• 2003

Aromatic hydrocarbons are of major concern among genotoxic chemicals due to their toxicity and persistence. Some microorganisms can utilize aromatic hydrocarbons as carbon and energy sources by inducing expression of catabolic operon(s). The XylR regulatory protein activates transcription of the catabolic enzymes to degrade BTEX (benzene, toluene, ethylbenzene, and xylene) from its cognate promoters, Pu and Ps upon exposure of the cells to the aromatic hydrocarbons. The activity of XylR on the promoters was previously monitored using luciferase luc reporter system. The xylR, its promoter Pr and the promoter Po for the phenolic compound catabolic operon were introduced upstream of firefly luciferase luc in the pGL3b vector to generate about 7.1 kb of pXRBTEX. Here E. coli harboring the plasmid was freeze-dried under various conditions to fin,d optimal conditions for storage and transport. The cell viability and luciferase activity were maintained better, when the cells were freeze-dried at -7$0^{\circ}C$ in the addition of the 10% skim milk or 12% sucrose. However, coaddition of protectants such as 10% skim milk plus 10% glucose or 12% sucrose plus 10% glucose, resulted in much better viability and bioluminescence activity compared with the effect of single addition of each protectant. In addition, it was shown that the freeze-dried cells maintained almost intact bioluminescent activities and cell viability for at least 1 week after freeze-drying. This work demonstrated that the properly freeze-dried recombinant bacterial cells could be utilized as a whole-cell biosensor for simple and rapid monitoring of BTEX in the environment.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권1호
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• pp.89-92
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• 2011

Herpes simplex is caused by viruses of the herpesvirus hominus family. HSV have four categories: type 1, 2, 6, and 8. Generally HSV-1 affects the mouth. Once infected by HSV, the person's infection is permanent. Retrograde transport through adjacent neural tissue to sensory ganglia leads to a lifelong latent infection. Recently, we treated a patient with recurrent herpes-stomatitis mimicking acute necrotizing ulcerative gingivitis (ANUG). The results were satisfactorty so we report this case. 31 years old male patient showed sore throat, gingival ulceration, palpable both submandibular lymph node, and sulcular pus formation around posterior decayed teeth. This is the third time he has suffered from this symptom. Tentative diagnosis was acute necrotizing ulcerative gingivitis. Antibiotic therapy was started. But, intraoral symptom got worse in process of time. Especially ulcer of marginal gingiva got worse. Viral disease was suspected. We carried out viral cultivation. At the same time topical application of antiviral ointment (herpecid$^{(R)}$) was performed on oral ulcer unilaterally for the purpose of diagnosis and reducing pain experimentally. The next day pain was decreased dramatically on application area. Basing on the viral cultivation and clinical effect of antiviral ointment (herpecid$^{(R)}$), we have diagnosed it as a recurrent herpes-stomatitis and concluded that viral infection was major cause of disease and bacterial infection was secondary.

• Journal of Plant Biotechnology
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• 제35권2호
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• pp.141-145
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• 2008

본 연구는 남세균 고유의 프로모터를 포함하는 유전자간 염기서열에 기반하여 환경위해성 검출용 바이오센서를 개발하고자 시도되었다. 포도당 처리에 의해서 유도되는 8종의 유전자 (atpI, ndbA, ctaD1, tkt, pgi, pdh, ppc, 그리고 rydA)의 프로모터 부위를 리포터 유전자의 일종인 발광유전자 (luxAB) 벡터 pILA (Genbank: AJ251840)에 도입시켜 재조합 벡터를 제조한 후 Synechocystis sp. PCC6803을 형질전환시킨 결과, pILA 벡터만을 포함하고 있는 대조구에 비해서 포도당 처리에 의해서 생물발광량이 5-25배 정도 현저히 증가함을 확인하였다. 또한 $Hg^{2+}$, $Cu^{2+}$, $Zn^{2+}$과 같은 중금속, $CN^-$, DCMU, DBMIB와 같은 제초제, 그리고 클로람페니콜이나 리팜피신과 같은 항생제에 의해서 생물발광이 현저히 억제되었다.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.428-437
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• 2007

The potential for humic substances to serve as terminal electron acceptors in microbial respiration and the effects of humic substances on microbial azoreduction were investigated. The dissimilatory azoreducing microorganism Shewanella decolorationis S12 was able to conserve energy to support growth from electron transport to humics coupled to the oxidation of various organic substances or $H_2$. Batch experiments suggested that when the concentration of anthraquinone-2-sulfonate (AQS), a humics analog, was lower than 3 mmol/l, azoreduction of strain S12 was accelerated under anaerobic condition. However, there was obvious inhibition to azoreduction when the concentration of the AQS was higher than 5 mmol/l. Another humics analog, anthraquinone-2-sulfonate (AQDS), could still prominently accelerate azoreduction, even when the concentration was up to 12 mmol/l, but the rate of acceleration gradually decreased with the increasing concentration of the AQDS. Toxic experiments revealed that AQS can inhibit growth of strain S12 if the concentration past a critical one, but AQDS had no effect on the metabolism and growth of strain S12 although the concentration was up to 20 mmol/l. These results demonstrated that a low concentration of humic substances not only could serve as the terminal electron acceptors for conserving energy for growth, but also act as redox mediator shuttling electrons for the anaerobic azoreduction by S. decolorationis S12. However, a high concentration of humic substances could inhibit the bacterial azoreduction, resulting on the one hand from the toxic effect on cell metabolism and growth, and on the other hand from competion with azo dyes for electrons as electron acceptor.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3188-3194
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• 2014

Compound K (CK) was formulated as polymeric micelles (PM) using Pluronic$^{(R)}$ F-127 to enhance the oral absorption of CK, an intestinal bacterial metabolite of ginseng protopanaxadiol saponin. The physicochemical properties of Ck-loaded PM were characterized and an in vitro transport study using the Caco-2 cell system as well as an in vivo pharmacokinetic study using SD rats was carried out. The hydrodynamic mean particle size of CK-loaded PM (CK-PM) was $254{\pm}23.45nm$ after rehydration and the drug loading efficiency was ca. 99.9%. The FT-IR spectroscopy, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy data supported the presence of a new solid phase in the PM. The $P_{app}$ value of in vitro Caco-2 cell permeation of CK-PM and the oral absorption of CK was enhanced about 1.2-fold and 2.6-fold compared to CK suspension, respectively, showing that the present PM formulation enabled an enhancement of oral CK absorption.

• 생명과학회지
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• 제15권2호
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• pp.304-310
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• 2005

생체세포에 대한 paraquat의 독작용은 superoxide dismutase 활성저해에 기인하는 것으로 알려져 있다. 그러나 세균이 paraquat에 매우 짧은 시간동안의 노출에 의하여서도 독작용을 받을 수 있는 것으로 검토됨에 따라 paraquat의 독작용의 하나로서 전자전달에 미치는 영향 중 NAD(H)의 산화 및 환원반응에 미치는 영향을 검토한 결과는 다음과 같다. 공시균의 원형질막 획분, rat mitocondria분산액 및 NAD-dependent dehydrogenase에 의한 산화 및 환원시 paraquat 첨가구에서 반응 Graph의 경사도가 더 컸으며, 반응 개시점 및 종결점이 대조구에 비해 낮은 결과로 반응이 가속화되는 결과를 볼 수 있었다. 반응을 경시적으로 NAD(H)의 함량변화로 검토한 결과에서도 원형질 막 획분과 rat mitocondria 분산액을 이용한 경우에 10분간의 NADH산화량이 대조구는 각각 960 mM, 1,187 mM이었으나 Paraquat 처리구는 각각 1,200 mM, 1,434 mM로 Paraquat 처리구가 반응 가속화 경향을 보였다. NAD(H) dependent dehydrogenase에 의한 NAD(H)의 산화 및 환원 반응에서도 대조구에 비하여 Paraquat 처리구가 초기반응의 가속화 및 총산화량의 증가를 보였다.

• 약학회지
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• 제40권1호
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• pp.102-111
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• 1996

LB10522 is a new parenteral broad spectrum cephalosporin with a catechol moiety at C-7 position of beta-lactam ring. This compound can utilize tonB-dependent iron transp ort system in addition to porin proteins to enter bacterial periplasmic space and access to penicillin-binding proteins (PBPs) which are the lethal targets of ${\beta}$-lactam antibiotics. The chelating activity of LB10522 to metal iron was measured by spectrophotometrically scanning the absorbance from 200 to 900nm. When $FeCl_3$ was added, optical density was increased between 450 and 800nm. LB10522 was more active against gram-negative strains in iron-depleted media than in iron-replete media. This is due to the increased expression of iron transport channels in iron-depleted condition. LB10522 showed a similar activity against E. coli DC2 (permeability mutant) and E. coli DCO (wild type strain) in both iron-depleted and iron-replete media, indicating a minimal permeaility barrier for LB10522 uptake. LB10522 had high affinities to PBP 3 and PBP 1A, 1B of E. coli. By blocking these proteins, LB10522 caused inhibition of cell division and the eventual death of cells. This result was correlated well with the morphological changes in E. coli exposed to LB10522. Although the in vitro MIC of LB10522 against P. aeruginosa 1912E mutant (tonB) was 8-times higher than that of the P. aeruginosa 1912E parent strain, LB10522 showed a similar in vivo protection efficacy against both strains in the mouse systemic infection model. This result suggested that tonB mutant, which requires a high level of iron for normal growth, might have a difficulty in surviving in their host with an iron-limited environment.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 Proceedings of the 17th Symposium on Plant Biology Environmental Stress and Photosynthesis
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• pp.83-90
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• 1999

Electron crystallography of two-dimensional crystalsand electron cryo-microscopy is becoming an established method for determining the structure and function of a variety of membrane proteins that are providing difficult to crystallize in three dimension. In this study this technique has been used to investigate the structure of a ~160 kDa reaction centre sub-core complex of photosystem II. Photosystem II is a photosynthetic membrane protein consisting of more than 25 subunits. It uses solar energy to split water releasing molecular oxygen into the atmosphere and creates electrochemical potential across the thylakoid membrane, which is eventually utilized to generate ATP and NADPH. Images were taken using Philips CM200 field emission gun electron microscope with an acceleration voltage of 200kW at liquid nitrogen temperature. In total, 79 images recorded dat tilt angles ranging from 0 to 67 degree yielded amplitudes and phases for a three-dimensional map with an in-plant resolution of 6$\AA$ and 11.4$\AA$ in the third dimension shows at least 23 transmembrane helices resolved in a monomeric complex, of which 18 were able to be assigned to the D1, D2, CP47 , and cytochrome b559 alfa beta-subunits with their associated pigments that ae active in electron transport (Rhee, 1998, Ph.D.thesis). The D1/D2 heterodimer is located in the central position within the complex and its helical scalffold is remarkably similar to that of the reaction centres not only in purple bacteria but also in plant photosystem I (PSI) , indicating a common evoluationary origin of all types of reaction centre in photosynthetic organism known today 9RHee et al. 1998). The structural homology is now extended to the inner antenna subunit, ascribed to CP47 in our map, where the 6 transmembrane helices show a striking structural similarity to the corresponding helices of the PSI reaction centre proteins. The overall arrangement of the chlorophylls in the D1 /D2 heterodimer, and in particular the distance between the central pair, is ocnsistent with the weak exciton coupling of P680 that distinguishes this reaction centre from bacterial counterpart. The map in most progress towards high resolution structure will be presented and discussed.

• Journal of Dairy Science and Biotechnology
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• 제41권4호
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• pp.203-210
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• 2023

Bacterial contamination negatively affects the quality, functionality, and safety of dairy products. Adherent populations of bacteria, referred to as biofilms, grow on the surfaces of dairy processing equipment and are the primary cause of dairy contamination. In addition, microorganisms present in the farm environment and dairy factory can contaminate the Clear-In-Place (CIP) line through raw milk transport pipes; therefore, exhaustive management is required. In dairy manufacturing facilities, biofilm formation is controlled using CIP systems that primarily require sodium hydroxide and nitric acid. However, the leakage or incomplete removal of these potently active compounds can be harmful to humans. In the present study, we compared the eradication of Escherichia coli and other bacteria using commercially available combinations of sodium hypochlorite (NaClO) and citric acid, which are recognized by the Korean Ministry of Food and Drug Safety (MFDS) as food disinfectants. When considered in the CIP system of the field manufacturing process, E. coli was not detected (compared to detection before treatment), and other bacteria were detected at 0-32 culture-forming units (CFU)/cm². The residual amount of chlorine ions after CIP treatment was similar to that in tap water, and there was no significant difference in the overall components of the fermented dairy products. Therefore, the NaClO/citric acid CIP system can be safely applied in dairy manufacturing processes.