• Journal of Microbiology and Biotechnology
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• v.28 no.1
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• pp.77-86
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• 2018

The human pathogen and food spoiler Bacillus cereus can form biofilms that act as a persistent source of contamination, which is of public health concern. This study aimed to understand how the source of isolation might affect the behavior of biofilm formation. Biofilm formation abilities of 56 strains of B. cereus isolated from different environments, including human food poisoning, farm, and food, were determined. Crystal violet assay results revealed significant (p < 0.05) differences in biofilm formation abilities among the strains isolated from different sources only at an early stage of incubation. However, strain origin showed no impact on later stage of biofilm formation. Next, correlation of the group of isolates on the basis of their biofilm-forming abilities with the number of sessile cells, sporulation, and extracellular polymeric substance (EPS) formation was determined. The number of sessile cells and spores in biofilms was greatly influenced by the groups of isolates that formed dense, moderate, and weak biofilms. The contribution of extracellular DNA and/or proteins to EPS formation was also positively correlated with biofilm formation abilities. Our results that the source of isolation had significant impact on biofilm formation might provide important information to develop strategies to control B. cereus biofilm formation.

• Natural Product Sciences
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• v.2 no.2
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• pp.130-136
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• 1996

Evaluation of plant extracts that might inhibit hepatitis B virus (HBV) replication was performed to find potent anti-HBV agents. Eighty-five species of plants from forty-three families were tested for their anti-HBV activities using HBV-producing HepG2-derived 2.2.15 cells. The anti-HBV activity of plant extracts was measured by slot blot hybridization technique and cytotoxicity was determined by crystal violet staining procedure. All plants were extracted with methanol and the extracts were partitioned into n-hexane, ethyl acetate and aqueous layer. The ethyl acetate fractions of Rhus verniciflua $(stem:\;EC_{50},\;8.2{\mu}g/ml;\;CC_{50},\;9.4{\mu}g/ml)$, Gastrodia elata $(root:\;EC_{50},\;17.7{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, Raphanus sativus $(seeds:\;EC_{50},\;17.3{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, and Angelica gigas $(root:\;EC_{50},\;8.3{\mu}g/ml;\;CC_{50},\;15.6{\mu}g/ml)$ revealed the anti-HBV activity in 2.2.15 cell culture system and these fractions are under the process of further sequential fractionation by column chromatography to find the active principles against HBV.

• The Journal of Korean Medicine
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• v.21 no.4
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• pp.183-192
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• 2000

Objectives : The present study was carried out to investigate the effects of Danchun-hwan(DCH) on the peroxynitrite-induced neural cell death in human neuroblastoma cell line, SH-SY5Y. Methods : The cultured cells were pretreated with DCH and exposed to 3-morpholinosydnonimine(SIN-1) that simultaneously generates NO and superoxide, thus possibly forming peroxynitrite. The cell damage was assessed by using MTT assay and crystal violet staining. Results : Exposure of the cells to SIN-1 for 24hr induced 75% apoptotic cell death, as evaluated by the occurrence of morphological nuclear changes characteristic of apoptosis using 4', 6-diamidino-2-phenylinole(DAPI). However, pretreatment of SH-SY5Y with the water extracts of DCH, inhibited the apoptotic cell death in a dose-dependent manner. DCH also inhibited SIN-1-induced apoptotic caspase 3-like protease activity in a dose-dependent manner. DCH recovered the depleted glutathione levels by SIN-1. Conclusions : Taken together, it is suggested that DCH protected human neuroblastoma cell line, SH-SY5Y, from the free radical injury mediated by peroxynitrite by a mechanism of elevating antioxidant, GSH.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1525-1535
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• 2020

Synthetic dyes are widely used in various industries and their wastage causes severe environmental problems while being hazardous to human health, leading to the need for eco-friendly degradation techniques. The split-gill fungus Schizophyllum commune, which is found worldwide, has the potential to degrade all components of the lignocellulosic biomass and is a candidate for the treatment of synthetic dyes. A systematic molecular analysis of 75 Korean and 6 foreign S. commune strains has revealed the high genetic diversity of this population and its important contribution to the total diversity of S. commune. We examined the dye decolorization ability of this population and revealed 5 excellent strains that strongly decolorized 3 dyes: Crystal Violet, Congo Red and Methylene Blue. Finally, comparison of dye decolorization ability and the phylogenetic identification of these strains generalized their genetic and physiological diversity. This study provides an initial resource for physiological and genetic research projects as well as the bioremediation of textile dyes.

• Toxicological Research
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• v.18 no.2
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• pp.183-190
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• 2002

The mechanism by which catechin-mediated cytotoxicity against tumor cells remains to be elusive. To elucidate the mechanical mights of anti-tumor effects, (-)epigallocatechin-gallate (EGCG) of catechin was applied to human prostate cancer DU 145 cells. Cell viability was measured by crystal violet staining. Cell lysates were wed to measure the catalytic activity of caspases by using fluorogenic peptide: Ac-DEVD-AMC for caspase-3 protease, Z-IETD-AFC for caspase-8 protease, Ac-LEHD-AFC for caspase-9 protease as substrates. The equal amounts of protein from cell lysate was separated on SDS-PAGE and analyzed by western blotting with anti-Fas antibody, anti-FasL antibody, anti-BCL2 antibody and anti-Bax antibody. (-)EGCG induced the death of DUl45 cells, which was revealed as apoptosis shown by DNA fragmentation. (-)EGCG induced the activation of caspase family cysteine proteases including caspase-3, -8 and -9 proteases in DU145 cells. Also, (-)EGCG increased the expression of Fas and Fas ligand (FasL) protein in DU145 colls. The expression level of BCL2 was decreased in (-)EGCG treated DU145 cells, whereas Bax protein was increased in a time-dependent manner. We suggest that (-)EGCG-induced apoptosis of DU145 cells is mediated by signaling pathway involving caspase family cysteine protease, mitochondrial BCL2-family protein and Fas/FasL.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.2
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• pp.328-332
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• 2008

The purpose of this study was to identify the protective effect of Codonopis pilosula extract on cell death induced by $H_2O_2$ in SK-N-MC neuroblastoma cells. We measured the antioxidant effect by DPPH radical scavenging analysis, BSA analyssis and examined the cell viability by crystal violet and cytochrome C, Bax, Bcl-2, p53, p21 by using Western blot analysis. Codonopis pilosula extract scavenged DPPH radical in a dose-dependent manner and shown direct free radical scavenging effect, suggested that Codonopis pilosula extract have antioxidant effect in vitro. Treatment of cells with hydrogen peroxide, a reactive oxygen species, was to induce cell death and pretreatment with Codonopis pilosula extract attenuated the occurrence of $H_2O_2-induced$ cell death. To elucidate the protective mechanisms of action of Codonopis pilosula extract, Western blot analyses for Bcl-2 and Bax expression and cytochrome c release were carried out. Pretreatment with Codonopis pilosula extract induced the expression of Bcl-2 and suppressed the release of cytochrome c and Bax into the cytosol, thereby arresting $H_2O_2-induced$ apoptotic cell death. Especially p21 and p53 were decreased prior to $H_2O_2$ treatment. These results suggest that Codonopis pilosula extract is associated with the cell cycle and anti-apoptotic cell death.

• Environmental Analysis Health and Toxicology
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• v.8 no.3_4
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• pp.7-12
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• 1993

An Actinomycete strain isolated from Mt. Dea-Dun had a strong antifungal activity. The culture brith produced by isolated strain showed only antifungal activity against fungi with the exception of yeast and bacteria. It was heat stable, dissolved in ehtylacetate. The concentrated antifungal agent showed cytotoxicity against HEP-2 and HeLa as tumor cell line, and showed weak cytotoxicity against VERO 36 as normal cell line. Morphological and physiological characteristics were tested with isolated strain. The spore color of isolated strain was gray. It had a short chain and produced brown colored lytic substance in yeast extract-malt agar. The cell wall of isolated strain was composed of meso-DAP, and we suggested it as genus Actinomadura. In the existing of chemical inhibitor, isolated strain grew on the condition of 0.0001% crystal violet, 0.1% phenol, 0.01% sodium azide and 10% sodium chloride. Carbon utilization of isolated strain was shown that glucose, sucrose, manitol and sodium citrate were well utilized.

• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.82-89
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• 1989

The fluorescence of $Eu^{3+},\;Tb^{3+}$ substituted for $La^{3+}$ in Lanthanum Oxychloride (LaOCl) has been studied. The fluorescence intensity of the $Eu^{3+},\;Tb^{3+}$ in LaOCl excited by Ultra-violet light were investigated on its activator concentration and discussed as the energy transfer process. The energy transfer from $Tb^{3+}\;to\;Eu^{3+}$ take place in the $Eu^{3+}\;and\;Tb^{3+}$ codoped LaOCl crystal. This process was confirmed to the change of concentration and the measurement of fluorescence decay time.

• Restorative Dentistry and Endodontics
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• v.7 no.1
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• pp.131-138
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• 1981

The purpose of this study was to evaluate the marginal leakage of composite resin. Preparing 144 class V cavities on freshly extracted noncarious teeth, composite resins were prepared and inserted by one dentist according to the manufacturer's instructions. The experiments were performed in two different groups; In group I; Class V cavities with $90^{\circ}$ cavosurface angle, In group II; Class V cavities with $135^{\circ}$ cavosurface angle. And each group was divided 2 subgroups; In control group; composite resin restoraions without acid etch technique. In experimental group; composite resin restorations with acid etch technique. All specimens were immersed in 0.05% crystal violet solution. Before examination, the restored teeth were subjected to thermal stress. The specimens were sectioned occlusogingivally through the center of the restorations with a diamond disk. The sections were examined under a reflected light microscope at 1 day, 7 days and 30 days after immersing the specimens in dye solution. The results were as follows; 1. Control group of group I and group II showed marginal leakage. 2. The degree of marginal leakage in experimental group was greater reduced than control group. 3. In control group, the degree of marginal leakage in group I was greater than group II. 4. In experimental group, there is not statistical differences of the degree of marginal leakage between group I & group II.

• International Journal of Oral Biology
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• v.46 no.3
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• pp.111-118
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• 2021

Periodontitis and periimplantitis are caused as a result of dental biofilm formation. This biofilm is composed of multiple species of pathogens. Therefore, controlling biofilm formation is critical for disease prevention. To inhibit biofilm formation, sugars can be used to interrupt lectin-involving interactions between bacteria or between bacteria and a host. In this study, we evaluated the effect of D-Arabinose on biofilm formation of putative periodontal pathogens as well as the quorum sensing activity and whole protein profiles of the pathogens. Crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy revealed that D-Arabinose inhibited biofilm formation of Porphyromonas gingivalis, Fusobacterium nucleatum, and Tannerella forsythia. D-Arabinose also significantly inhibited the activity of autoinducer 2 of F. nucleatum and the expression of representative bacterial virulence genes. Furthermore, D-Arabinose treatment altered the expression of some bacterial proteins. These results demonstrate that D-Arabinose can be used as an antibiofilm agent for the prevention of periodontal infections.