• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.88-95
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• 2013

Candida biofilms are self-organized microbial communities growing on the surfaces of host tissues and medical devices. These biofilms have been displaying increasing resistance against conventional antifungal agents. The roots of Scutellaria baicalensis have been widely used for medicinal purpose throughout East Asia. The aim of the present study was to evaluate the effect of S. baicalensis aqueous extract upon the preformed biofilms of 10 clinical C. albicans isolates, and assess the mechanism of the antibiofilm activity. Its effect on preformed biofilm was judged using an XTT reduction assay and the metabolic activity of all tested strains were reduced ($57.7{\pm}17.3$%) at MIC values. The S. baicalenis extract inhibited (1, 3)-${\beta}$-D-glucan synthase activity. The effect of S. baicalensis on the morphology of C. albicans was related to the changes in growth caused by inhibiting glucan synthesis; most cells were round and swollen, and cell walls were densely stained or ruptured. The anticandidal activity was fungicidal, and the extract also arrested C. albicans cells at $G_0/G_1$. The data suggest that S. baicalensis has multiple fatal effects on target fungi, which ultimately result in cell wall disruption and killing by inhibiting (1, 3)-${\beta}$-D-glucan synthesis. Therefore, S. baicalensis holds great promise for use in treating and eliminating biofilm-associated Candida infections.

• Journal of Korean Society of Disaster and Security
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• v.13 no.2
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• pp.65-75
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• 2020

The efficiency of sewage treatment was ananlyzed selecting a sewage treatment plant in Gyeonggi-do where A₂O process was applied. Statistical techniques based on the operation data of the sewage treatment were used. The main factors directly affecting the efficiency of the treatment process were analyzed using a GPS-X model. The correlation analysis and one-way ANOVA were performed. The T-N and NH₄⁺-N values of the effluent did not generate statistically significant level (p-value:>0.05) when compared with C/N ration values. Removel of nitrogen components form sewage treatment plants were affected by temperature, HRT, SRT and DO. In the case of BOD, all operating factors were affected, while COD was affecte by factors of HRT, STR and DO. In simulations using GPS-X, the parameters that greatly influence was included the maximum sedimentation rate, the dependent nutrient microbial yield (anoxic), the phosphorus saturation coefficient, the dependent nutrient microbial killing rate, the dependent nutrient microbial maximum growth rate, and the independent trophic microorganisms. The maximum growth rate and the maximum setting rate were identified.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2001.06a
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• pp.149-153
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• 2001

To investigate the mode of bactericidal action for antimicrobial peptide, pediocin, synthetic and mutant pediocins were prepared by direct chemical synthesis. Native pediocin was purified from Pedio-coccus acidilactici M and its conformational structure and bactericidal functions were analyzed and compared to synthetic pediocin. Schematic mode of pediocin actions, how pediocin binds on the target cell membrane, penetrates and makes tunnel are proposed. For these purposes, primary and secondary structures of pediocin was analyzed and disulfide bond assignment was also done. The pediocin purified from P. acidilactici M had high effective bactericidal ability against gram positive bacteria, especially Listeria monocytogenes and was very stable at extreme pHs and even at high temperatures such as autoclaving temperature (121$^{\circ}C$). Pediocin was consisted of 44 amino acids with four cysteines. Novel synthetic peptides were achieved by solid phase peptide synthesis(SPPS) method. To explain the function of cysteine in C-terminal region, mutant pediocin, Ped[C24A＋C44A], was synthesized and their structural and biological functions were analyzed. Second mutant pediocin, Ped[KllE], was prepared to explain the function of lysine at 11 of N-terminal part of pediocin, especially loop of $\beta$-sheet, and to predict the initial binding site of pediocin. The native and synthetic pediocins was showed random coil conformation by spectropolarimetry in moderate conditions. This conformation was observed in extreme conditions such as high temperature and low and high pHs, also. Circular dichroism(CD) data also showed the existence of $\beta$-turn structure in N-terminal part both native and synthetic pediocins. A structural model for pediocin predicts that 18 amino acids in the N-terminal part of the peptide assume a three-strand $\beta$-sheet conformation. This random coil in C-terminal part of pediocin was converted to folding structure, helix structure, in nonpolar solvents such as alcohol and TFE. The disulfide bond between $^{9}$ Cys and $^{14}$ Cys was concrete and inevitable, however, evidences of disulfide bond between $^{24}$ Cys and $^{44}$ Cys was not. Data of Ped[C24A＋C44A], pediocin mutant showed that $^{44}$ Cys was required during killing the target cells but not inevitable, since Ped[C24A＋C44A] still have bactericidal activity but much less than native pediocin. Another pediocin mutant, Ped[KllE], had still bactericidal activity, was controversial to propose that positive charge like as $^{11}$ Lys in loop or hinge in bacteriocin bound or helped to binding to microorganism with electrostatic interaction between cell membrane especially teichoic acid and positive amino acid nonspecifically. The conformation of pediocin among native, synthetic and mutant pediocins did not show big difference. The conformations between oxidized and reduced pediocin were almost similar regardless of native or synthetic.

• The Journal of Internal Korean Medicine
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• v.27 no.2
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• pp.379-393
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• 2006

Objectives: We are aimed to identify anti-tumor effects of Curcuma aromatics on some kinds of cancer cells through molecular biologic methods. Materials & Methods: We used 4 kinds of cancer cell lines such as lung cancer cells(AS49), cervical cancer cells(HeLa), glioma cancer cells(A172) and prostate cancer cells(PC3). We treated the boiled extract of Curcuma aromatica $5{\mu}g,\;10{\mu}g$ to cultural media(ml) for 24 hours. We measured the cytotoxicitv on 4 kinds of cancer cells through tryphan blue exclusion test and the suppressive effect on viability of 4 kinds of cancer cells via MTT assay. We measured change of mitochondria membrane potential via flow cytometry. The quantitative RT-PCR was used to examine the effect on the revelation of Bcl-2 and Bax which are genes related to apoptosis. We examined the effect on the revelation of Bcl-2 Protein and Bar protein by western blot analysis. Results : In the experiment of tryphan blue exclusion test, the extract of Curcuma aromatica showed more significant killing effect on AS49, HeLa than the control group with density dependent manner, which was statistically significant. In the experiment of MTT assay the extract of Curcuma aromatica showed more suppressive effect on viability of A549, HeLa than the control group with density dependent manner, which was statistically significant. Curcuma aromatica induced apoptosis by decreasing the membrane potential of mitochondria in A549, HeLa. In the experiment of the revelation of genes related to apoptosis, the revelation of Bcl-2 decreased and the revelation of Bax increased in A549, HeLa treated with Curcuma aromatica with dose dependent manner. In the experiment of the revelation of protein related to apoptosis, the protein levels of Bcl-2 decreased and the protein levels of Bax increased in AS49, HeLa treated with Curcuma aromatica with dose dependent manner. Conclusions: From this study, we can infer that Curcuma aromatica has anti-tumor effect on lung cancer cells and uterine carcinoma cells but not on glioma cells and prostate cancer cells.

• The Journal of Internal Korean Medicine
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• v.23 no.1
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• pp.99-106
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• 2002

Background : Nowadays a lot of research is based on natural substances or materials world wide since many kinds of side effects are accompanied by anti tumor chemotherapy. In Chinese medicine, Dioscorea bulbifera L is widely used to treat many kinds of cancer, but in Korea it is rarely used. Therefore, we need to scientifically identify anti tumor effects of Dioscorea bulbifera L. Objective : We aimed to identify anti tumor effects of Dioscorea bulbifera L on the stomach cancer cells through molecular biological methods. Materials & Methods : We used AGS, a stomach cancer cell from American Type Culture Collection. We injected the boiled extract of Dioscorea bulbifera L 5 ul(sample 1), 10ul(sample 2) to cultured media(ml) for 0,6,12,18,24 hours. We measured the killing effect on stomach cancer cells through Tryphan blue exclusion test and suppressive effect on viability of stomach cancer cells via MTT assay. Results : Tryphan blue exclusion test showed that each test group killed more stomach cancer cells than the controlled group with a dosage-dependent, but not significantly. MTT assay showed that each test group had a more suppressive effect on viability of stomach cancer cells than the controlled group without a dosage-independent, but not significantly. The cell cycle analysis via flow cytometry showed that the test group extended cell cycle, and there was no peak in M phase, the number of sub G1, G0, G1 phase cells increased a little, but not significantly. Conclusion : This experiment showed that Dioscorea bulbifera L. has an anti-tumor effect, but not significantly. This is in vitro experiment and basic experiment on Dioscorea bulbifera L. We hope more progressive researches on Dioscorea bulbifera L. will be conducted and its anti tumor will be more accurately identified.

• Journal of Life Science
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• v.19 no.6
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• pp.799-803
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• 2009

The killing of male germ cells by radiation and other toxicants has recently been attributed to apoptosis, but a critical evaluation of the presence of the different features of apoptosis in each epithelial stage has not been performed. In this study, mouse testes exposed to radiation were examined by light microscopy and terminal transferase-mediated end labeling (TUNEL) with periodic acid-Schiff (PAS) stains to determine whether the cells were apoptotic according to several criteria. Apoptosis was easily recognized by the presence of peroxidase-stained, entirely apoptotic bodies. In the TUNEL-positive cells or bodies, the stained products correlated precisely with the typical morphologic characteristics of apoptosis as seen at the light microscopic level. The changes that occurred from 0 to 24 hours after exposing the mice to 2 Gy of gamma-rays (2 Gy/min) were examined. The numbers of apoptotic cells reached a peak at 12 hours after irradiation and then declined. The mice that received 0-8 Gy of gamma-rays were examined 8 hours after irradiation. Dose-response relationships were generated for each stage of the epithelial cycle by counting TUNEL-positive cells. The dose-response curves were linear- quadratic [y=(-0.014${\pm}$0.009)$D^{2}$+(0.31${\pm}$0.697)D+0.3575. Where y=the number of apoptotic cells per seminiferous tubule, and D=the irradiation dose in Gy, $r^{2}$=0.9] and there was a significant relationship between the frequency of apoptotic cells and the radiation dose. Although the maximum response was produced by 8 Gy, even 0.5 Gy induced marked changes. These changes were most pronounced in B spermatogonia of stage V and the spermatocyte at the mitotic cells of stage XII.

• Radiation Oncology Journal
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• v.5 no.2
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• pp.83-95
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• 1987

The synergistic effect of combining radiation therapy and hyperthermia kills significantly more cells than using either modality alone. The reason for enhanced cell killing from the combined treatment is that the two modalities are complementary. For histopathological exmination, 102 rats were divided into 4 groups as hyperthermia, radiation, hyperthermia combined with radiation and normal control groups. The effect of prior irradiation (6-15 Gy of X-ray) on the response of small and large bowel of rats to $40^{\circ}C-44^{\circ}C$ (for 30 minutes) microwave (2450 MHz) hyperthermia was investigated. The musculature of the small and large intestine remained intact and the circumference of the histological sections were not significantly altered by the heated at $43^{\circ}C$ for 30 minutes. Thermal enhancement ratios of normal tissue is 1.0 Thermal enhancement ratio was not increased in combination therapy by evaluation of histopathologic changes in small and large intestine.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.483-487
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• 2016

The purpose of this study is to investigate whether gold nanoparticles had radiosensitization when combined with gamma and x ray beam. Cytotoxicity was mearsured with comparing survival fraction after incubated time 6,12,18 and 24 hours. Clonogenic assay was employed to assess survival fraction of cells with and without gold nanoparticles treatment following gamma ray irradiation. The most of gold nanoparticles were distributed in the cytoplasm. And the toxicity of gold nanoparticles used this study were found to be non-cytotoxic. And we also observed enhancement by about 40% in RBE value for gamma ray irradiation of cells treated with gold nanoparticles. Dose reduction of about half for gamma ray irradiation is demonstrated for gold nanoparticles treated cells as compared to untreated cells. In cells with exposed to gamma ray, DNA damage was increased when compared to only radiation exposed cells. The study revealed a significant reduction in radiation dose for killing the cells with internalized gold nanoparticles as compared to the cells without gold nanoparticles. The gold nanoparticles treatment resulted in enhancement of radiation effect as evident from increase in relative biological effectiveness values for photon irradiated cells.

• Parasites, Hosts and Diseases
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• v.35 no.3
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• pp.189-196
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• 1997

The purpose of this study is to determine whether nitric oxide is involved in the extracellular killing of Trichomoncs uasinalis by mouse (BALB/c) peritoneal macrophages and RAW264.7 cells activated with LPS or rIFN-γ and also to observe the effects of various chemicals which affect the production of reactive nitrogen intermediates (RNl) in the cytotoxicity against T. vnginnlis. The cytotoxicity was measured by counting the release of (3H)-thymidine from labelled protozoa and NOa was assayed by Griess reaction. Nemonomethyl-L-arginine (L-NMHA), Nenitro-L-arginine methyl ester (NAME) and arginase inhibited cytotoxicity to T. vaginnlis and nitrite production by activated mouse perioneal macrophagrs and RAW 264.7 cells. The addition of excess L-arginine competitively restored trichomonacidal activity of macrophages. Exogenous addition of FeSO4 inhibited cytotoxicity to T. vaginaLis and nitric products of macrophages. From above results, it is assumed that nitric oxide plays an important role in the host defense mechanism of macrophages against T ucfinalis.

• Membrane Journal
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• v.30 no.3
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• pp.158-172
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• 2020

In the aspect of saving energy and water, facilitating the separation membrane for the water treatment has been rising recently as one of the possible solutions. However, microbial biofouling effect is the biggest obstacle that hinders reaching higher permeability over a prolonged period of nanofiltration operation. To solve this problem and fully utilize the filtration membranes with enhanced performance, largely two kinds of solutions are studied and the first and the most commonly mentioned type is the one using the silver nanoparticles. Since silver nanoparticles are important to be well tailored on membrane surface, various methods have been applied and suggested. Using silver nanoparticles however also has the drawbacks or possible toxicity risks, raising the need for other types of utilizing non silver particles to functionalize the membrane, such as copper, graphene or zinc oxides, and amine moieties. Each attempt included in either kind has produced some notable results in killing, preventing, or repelling the bacteria while at the same time, left some unsolved points to be evaluated. In this review, the effects of metal nanoparticles and other materials on the antifouling properties of water treatment membranes are summarized.