• Journal of Ginseng Research
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• 제38권2호
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• pp.136-145
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• 2014

Background: This study aimed to develop a biocontrol system for ginseng root rot caused by Fusarium cf. incarnatum. Methods: In total, 392 bacteria isolated from ginseng roots and various soils were screened for their antifungal activity against the fungal pathogen, and a bacterial isolate (B2-5) was selected as a promising candidate for the biocontrol because of the strong antagonistic activity of the bacterial cell suspension and culture filtrate against pathogen. Results: The bacterial isolate B2-5 displayed an enhanced inhibitory activity against the pathogen mycelial growth with a temperature increase to $25^{\circ}C$, produced no pectinase (related to root rotting) an no critical rot symptoms at low [$10^6$ colony-forming units (CFU)/mL] and high ($10^8CFU/mL$) inoculum concentrations. In pot experiments, pretreatment with the bacterial isolate in the presumed optimal time for disease control reduced disease severity significantly with a higher control efficacy at an inoculum concentration of $10^6CFU/mL$ than at $10^8CFU/mL$. The establishment and colonization ability of the bacterial isolates on the ginseng rhizosphere appeared to be higher when both the bacterial isolate and the pathogen were coinoculated than when the bacterial isolate was inoculated alone, suggesting its target-oriented biocontrol activity against the pathogen. Scanning electron microscopy showed that the pathogen hyphae were twisted and shriveled by the bacterial treatment, which may be a symptom of direct damage by antifungal substances. Conclusion: All of these results suggest that the bacterial isolate has good potential as a microbial agent for the biocontrol of the ginseng root rot caused by F. cf. incarnatum.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.738-744
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• 2015

Tuberculosis is one of the most threatening infectious diseases to public health all over the world, for which Mycobacterium tuberculosis (MTB) is the etiological agent of pathogenesis. Ursolic acid (UA) has immunomodulatory function and exhibits antimycobacterial activity. However, the intracellular killing effect of UA has yet to be elucidated. The aim of this study was to evaluate the intracellular killing effect of UA during mycobacterial infection. The intracellular killing activity of UA was evaluated in the macrophage cell line THP-1 by the MGIT 960 system as well as by CFU count. The production of reactive oxygen species (ROS) and the level of nitric oxide (NO) were measured using DCF-DA and Griess reagent, respectively. Phagocytosis was observed by a fluorescence-based staining method, and the colony forming units were enumerated on 7H11 agar medium following infection. In addition, MRP8 mRNA expression was measured by qRT-PCR. UA significantly decreased the number of intracellular Mycobacterium through generation of ROS and NO. In addition, it profoundly activated the phagocytosis process of THP-1 cells during MTB-infection. Furthermore, our data demonstrated that UA activated the phagocytosis process in human monocyte cells through MRP8 induction. These data suggest that UA firmly contributes to the intracellular killing effect of macrophages during mycobacterial infection.

• 한국물환경학회지
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• 제16권4호
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• pp.469-477
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• 2000

Bisphenol-A (BPA), a known endocrine disruptor, is a main building block of epoxy resin which is widely used as a coating agent in residential water storage tanks. Therefore, BPA leaching from the epoxy resin may have adverse effects on human health. The possibility of BPA leaching from three epoxy resins were tested with a modified KS D 8502 method at 20, 50, 75 and $100^{\circ}C$ in deionized water and the specified test water, respectively. BPA leached to the test water was identified using GC-MS and quantified with GC-FID after a sequential extraction and concentration. The results showed that BPA leaching has occurred in all three samples tested. The quantify of BPA leaching from unit area of epoxy resin coating was in the range of $10.677{\sim}273.120{\mu}g/m^2$ for sample A, 29.737~1734.045 for sample B and 52.857~548.778 for sample C depending on the test temperature, respectively. In general, the amount of BPA leaching increased as the water temperature increases. This result implies a higher risk of BPA leaching to drinking water during a hot summer season. In addition, microbial growth, measured by colony forming units, in epoxy coated water tanks was higher than that in a stainless steel tank suggesting that compounds leaching from epoxy resin may support the growth of microorganisms in a residential water holding tank.

• 공업화학
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• 제7권5호
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• pp.963-969
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• 1996

에폭시 수지를 접착제의 base resin으로 이용하기 위해 DGEBA/dicy계의 경화특성을 조사하였다. dicy는 상온에서 저장안정성이 우수하여 일액형 접착제의 경화제로서 유용하다. 그러나 고온에서 경화시 열분해될 우려가 있으므로 경화온도를 낮추기 위해 diuron을 경화촉진제로 사용하였다. Epoxy/dicy계에서 dicy의 사용량이 증가함에 따라 경화반응열이 증가하였으며, 경화 후 수지의 유리전이온도($T_g$)도 증가하는 것으로 관찰되었다. Diuron을 경화촉진제로 사용함으로써 약 $40^{\circ}C$정도 낮은 온도에서 경화반응이 진행되었으며, 수지의 유리전이온도는 감소되었다. 경화반응의 속도론적 고찰은 Kamal이 제안한 자촉매반응의 모델식으로 해석하였으며, diuron의 경화촉진 효과를 확인할 수 있었다.

• 대한수의학회지
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• 제48권4호
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• pp.393-399
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• 2008

We investigated the potential of fucoidan for its ability to provide protection from gamma rayinduced damage. In our results, the fucoidan significantly improved the counts of endogenous colony forming unit to $9.5 {\pm} 1.5$, from $5.5 {\pm} 2.5$ compared with un-treated irradiated control group at 10 day after 7 Gy whole body irradiation. After 2 Gy irradiation, fucoidan treatment attenuated the percent of tail DNA of splenocytes, parameters of DNA damage, from $30.17 {\pm} 1.7%$ to $13.67 {\pm} 2.81%$ 2.81% by comet assay and also accelerated the proliferation of splenocytes, compared with un-treated irradiated control group by 3Hthymidine incorporation assay. Furthermore, fucoidan decreased the number of apoptotic fragments per intestinal crypt by 31.8% at 1 days after 2 Gy irradiation. These results indicated that the fucoidan significantly improved the hematopoietic recovery, prevented the DNA damage in immune cells and enhanced their proliferation, which had been suppressed by ionizing radiation. in addition, fucoidan rescued intestinal cells from radiation-induced apoptosis. Thus, this study raises the possibility of using fucoidan as adjuvant therapeutic agent after radiotherapy.

• 한국재료학회지
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• 제16권3호
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• pp.188-192
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• 2006

The microstructures and mechanical properties of continuously porous $SiC-Si_3N_4$composites fabricated by multi-pass extrusion were investigated at different Si levels added. Si-powder with different weight percentages (0%, 5%, 10%, 15%, 20%) was added to the SiC powder to make the raw mixture powders, with $6wt%Y_2O_3-2wt%Al_2O_3$ as sintering additives, carbon ($10-15{\mu}m$) as a pore-forming agent, ethylene vinyl acetate as a binder and stearic acid ($CH_3(CH_2)_{16}COOH$) as a lubricant. In the continuously porous $SiC-Si_3N_4$ composites, $Si_3N_4$ whiskers like the hairs of nostrils were frequently observed on the wall of the pores. In this study, the morphology of the $Si_3N_4$ whiskers was investigated with the silicon addition content. In the composites containing of 10 wt% Si, a large number of $Si_3N_4$ whiskers was found at the continuous pore regions. In the sample to which 15 wt% Si powder was added, maximum values of about 101 MPa bending strength and 57.5% relative density were obtained.

• 한국토양환경학회지
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• 제5권1호
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• pp.45-54
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• 2000

본 연구는 중금속(Zn, Cd)으로 오염된 토양을 여러 세척 용제(물, mineral acid, chelating agent, organic acld)를 가지고 탈착시켜 제거하는 실험으로 pH와 농도에 따라 회분식과 연속식 실험을 병행하였다. 물과 NaOH에 의한 세척 효과는 거의 없는 것으로 나타났으며 HCI, EDTA, Oxalic acid에 의한 세척 효과는 매우 높게 나타났다. HCI에 의한 세척효과가 가장 높은 이유는 낮은 pH에 의한 중금속의 이온화 현상에 의한 것으로 사료되며 EDTA, Oxalic acid의 효과가 높은 것은 용해도를 증가시켜 중금속 이온과 많은 착물을 형성하기 때문이다. 또한 Zn이 Cd보다 대체적으로 탈착율이 좋았으며 일반적으로 제거 경향은 pH가 낮을수록, 세척 용제의 농도가 높을수록 탈착율이 증가하였다. 중금속으로 오염된 토양 복원시 Zn의 세척 용제로는 HCI 과 EDTA를, Cd의 세척 용제로는 HCI과 Oxalic acid를 가지고 세척을 함으로써 효과적으로 정화되는 것을 알 수 있었다.

• 한국미생물·생명공학회지
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• 제2권3호
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• pp.127-131
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• 1974

Hydrocortisone에서 Prednisolone을 발효학적으로 제조함에 있어서 발생하는 산화분해 현상을 방지하기 위하여 저해제를 이용한 방법이 연구되었다. 첫째, A. simplex (ATCC 6946)의 생균을 사용하여 발효시키는 과정에서 Prednisolone이 분해된다는 현상을 밝혔다. 발효후 3시간만에 기질인 hydrocortisone의 72% 이상이 prednisolone으로 전환되었으나 시간이 경과하여 8시간이 지나면 이균의 생균세포는 상당량의 prednisolone을 산화 분해하였으며 한편으로는 분해중간산물을 생성하였다. 두째로는, prednisolone의 산화분해를 억제하기 위하여 $\alpha$$\alpha$'-dipyridyl과 같은 chelating agents를 발효액에 첨가하였다. 그 결과 이균의 생균세포에 의한 steroid 핵의 산화분해는 현저히 억제되었으며 또한 산화중간산물이 축적되었다. 이 중간산물은 $\alpha$$\alpha$'-dipyridyl의 첨가에 의하여 한층 현저하게 나타났다.

• Journal of Microbiology and Biotechnology
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• 제28권3호
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• pp.391-396
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• 2018

It is well known that Korean red ginseng has various biological activities. However, there is little knowledge about the antiviral activity of Korean red ginseng and its ginsenosides. In this study, we addressed whether oral administration of ginsenoside-Rb2 and -Rg3 is able to protect against rotavirus (RV) infection. The protective effect of ginsenosides against RV infection was examined using an in vivo experiment model in which newborn mice (10-day-old) were inoculated perorally (p.o.) with $1.5{\times}10^6$ plaque-forming units/mouse of RV strain SA11. When various dosages of ginsenoside-Rb2 (25-250 mg/kg) were administered 3days, 2 days, or 1 day before virus challenge, treatment with this ginsenoside at the dosage of 75 mg/kg 3days before virus infection most effectively reduced RV-induced diarrhea. In addition, consecutive administration of ginsenoside-Rb2 (75 mg/kg) at 3 days, 2 days, and 1 day before virus infection was more effective than single administration on day -3. The consecutive administration of ginsenoside-Rb2 also reduced virus titers in the bowels of RV-infected mice. In an experiment to compare the protective activity between ginsenoside-Rb2 and its two hydrolytic products (20(S)- and 20(R)-ginsenoside-Rg3), 20(S)-ginsenoside-Rg3, but not 20(R)-ginsenoside-Rg3, prevented RV infection. These results suggest that ginsenoside-Rb2 and its hydrolytic product, 20(S)-ginsenoside-Rg3, are promising candidates as an antiviral agent to protect against RV infection.

• Asian Pacific Journal of Cancer Prevention
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• 제15권12호
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• pp.5071-5076
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• 2014

Cholangiocarcinoma (CCA) is one of the aggressive cancers with a very poor prognosis. Several efforts have been made to identify and develop new agents for prevention and treatment of this deadly disease. In the present study, we examined the anticancer effect of luteolin on human CCA, KKU-M156 cells. Sulforhodamine B assays showed that luteolin had potent cytotoxicity on CCA cells with IC50 values of $10.5{\pm}5.0$ and $8.7{\pm}3.5{\mu}M$ at 24 and 48 h, respectively. Treatment with luteolin also caused a concentration-dependent decline in colony forming ability. Consistent with growth inhibitory effects, luteolin arrested cell cycle progression at the G2/M phase in a dose-dependent manner as assessed by flow cytometry analysis. Protein expression of cyclin A and Cdc25A was down-regulated after luteolin treatment, supporting the arrest of cells at the G2/M boundary. Besides evident G2/M arrest, luteolin induced apoptosis of KKU-M156 cells, demonstrated by a distinct sub-G1 apoptotic peak and fluorescent dye staining. A decrease in the level of anti-apoptotic Bcl-2 protein was implicated in luteolin-induced apoptosis. We further investigated the effect of luteolin on JAK/STAT3, which is an important pathway involved in the development of CCA. The results showed that interleukin-6 (IL-6)-induced JAK/STAT3 activation in KKU-M156 cells was suppressed by treatment with luteolin. Treatment with a specific JAK inhibitor, AG490, and luteolin diminished IL-6-stimulated CCA cell migration as assessed by wound healing assay. These data revealed anticancer activity of luteolin against CCA so the agent might have potential for CCA prevention and therapy.