• Journal of Life Science
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• v.18 no.1
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• pp.58-62
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• 2008

A novel agar-degrading bacterium SL-12 was isolated from seashore of Kijang at Busan, Korea, and cultured in marine broth 2216 media. Isolated bacterium SL-12 was identified as Glaciecola genus by 16S rDNA sequencing with 98% identity. The optimum pH of the enzyme activity was 7.0 and the optimum temperature for the reaction was $30^{\circ}C$. The enzyme hydrolyzed neoagarohexaose to yield neoagarobiose as the main product, indicating that the enzyme is ${\beta}$-agarase. Thus, isolated bacterium and the enzyme would be useful for the industrial production of neoagarobiose.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.71-73
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• 2017

본 논문에서는 4 방향 윤곽선 추적 기법과 히스토그램 분석 기법을 기반으로 한 개선된 FCM 알고리즘을 적용하여 색조 도플러 초음파 영상에서 상완 동맥의 혈류를 추출하고 분석하는 방법을 제안한다. 제안된 방법에서는 상완 동맥의 혈류를 정확히 추출하기 위해 전처리 과정으로 색조 도플러 초음파 영상 이외의 환자 정보가 있는 영역을 제거한 후, ROI 영역을 추출한다. 추출된 ROI 영역에서 영상의 최대 명암도를 임계치로 설정한 이진화 기법을 적용하여 ROI 영역을 이진화한다. 이진화된 ROI 영역에서 4 방향 윤곽선 추적 기법을 적용하여 상완 동맥이 존재하는 사다리꼴 형태의 영역을 추출한다. 색 정보를 분석한 히스토그램을 이용하여 특징점의 개수를 계산하고 계산된 특징점의 개수를 FCM 알고리즘의 초기 클러스터의 개수로 설정한 후, 추출된 사다리꼴 형태의 영역에 적용하여 양자화 한다. 양자화된 영역 중에서 빨간색으로 분류된 영역을 고혈압 영역으로 추출한다. 제안된 추출 방법을 20개의 색조 도플러 초음파 영상을 대상으로 실험한 결과, 20개의 색조 도플러 초음파 영상에서 18개의 색조 도플러 초음파 영상이 정확히 추출되었다.

• Environmental Mutagens and Carcinogens
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• v.25 no.4
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• pp.157-160
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• 2005

Antibiotic resistance of bacteria in the biofilm mode of growth contributes to the chronicity of infection and disease. The penetration of antibiotic, through biofilm developed in an itt vitro model system was investigated. Antibiotic resistant bacteria (E. coli) were obtained from Culture Collection of Antibiotic Resistant Microbes. Ca-alginate bead used as simulated biofilm and a cell entrapment test using compressed air were experiment for the improvement cell viability. Antibiotic susceptibilities though biofilms was measured by assaying the concentration of antibiotic that diffused through the biofilm to minimal inhibition concentration (MIC). Survival of immobilized cells were reduced as compared to free cells. In case of antibiotic susceptible E. coli reduced continuously, but antibiotic resistant E. coli kept up survival rate constantly. Survival was showed after exposed to the antibiotics that the more treated antibiotic resistant E. coli and low concentration of antibiotics) the more survived.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1116-1122
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• 2011

In this study, site-directed mutagenesis was performed on the ${\beta}$-agarase AgaA gene from Zobellia galactanivorans to improve its catalytic activity and thermostability. The activities of three mutant enzymes, S63K, C253I, and S63K-C253I, were 126% (1,757.78 U/mg), 2.4% (33.47 U/mg), and 0.57% (8.01 U/mg), respectively, relative to the wild-type ${\beta}$-agarase AgaA (1,392.61 U/mg) at $40^{\circ}C$. The stability of the mutant S63K enzyme was 125% of the wild-type up to $45^{\circ}C$, where agar is in a sol state. The mutant S63K enzyme produced 166%, 257%, and 220% more neoagarohexaose, and 230%, 427%, and 350% more neoagarotetraose than the wild-type in sol, gel, and nonmelted powder agar, respectively, at $45^{\circ}C$ over 24 h. The mutant S63K enzyme produced 50% more neoagarooligosaccharides from agar than the wild-type ${\beta}$-agarase AgaA from agarose under the same conditions. Thus, mutant S63K ${\beta}$-agarase AgaA may be useful for the production of functional neoagarooligosaccharides.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1321-1326
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• 2006

Total ginsenosides were purified and their antioxidant, antibacterial and anticancer activities were measured. The crude extracts of ginseng, which were extracted with 75% ethanol by ultrasonification method, were firstly purified on AB-8 macroporous adsorption column to remove water soluble impurities, and decolored on Amberlite IRA 900 Cl anion-exchange column. Then, they were purified on Amberlite XAD16 adsorption column to delete the non-polar impurities. Total ginsenosides contents of the purified extracts were 79.4%, 71.7% and 72.5% in cultured wild ginseng, red ginseng and white ginseng, which were significantly increased than those of crude extracts. All of the three extracts showed concentration-dependant scavenging activities against DPPH radicals, among which white ginseng showed the most powerful activity. Cultured wild ginseng roots showed strongest effect against both B. subtilis PM 125(Gram-positive) and E. coli D31 (Gram-negative) bacteria, while red ginseng and white ginseng only showed the activity against B. subtilis. According to the result of the MTT assay, ail of the three extracts inhibited the growth of U-937 human hohistiocytic lympma cell, which were significantly different (p < 0.05) when compared to the control.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.131-137
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• 2021

This study aimed at isolating lactic acid bacteria with anti-MRSA (methicillin-resistant Staphylococcus aureus) bacteriocin activity from fermented shrimp. We selected three strains, named Weissella sp. S1, S2, and S3, using analysis based on 16S rRNA gene sequences. All strains showed appropriate growth in an MRS medium containing 5% (w/v) NaCl and showed antibacterial activities against Bacillus cereus, Escherichia coli, Staphylococcus aureus, and MRSA. The strains exhibited similar growth rates at 0-5% NaCl, with approximate reduction in growth rate observed at 9% NaCl. Weissella sp. S1, S2, and S3 exhibited maximum growth rates at pH 7, 9, and 8, respectively. The crude bacteriocin was prepared from Weissella sp. S3 and subjected to characterization. The remaining activities after 30 min of exposure at each temperature were 100%, beyond 75%, and 49% at 4℃ and 37℃, 50℃ and 70℃, and 100℃, respectively. The remaining activities after 24 h of exposure at each pH were 100%, 75%, and 49% at pH 3 and 5, 7 and 9, and 10, respectively. Use of 50% (v/v) ethanol or isopropanol treatment did not diminish the antibacterial activity of the bacteriocin, while the 50% (v/v) hexane treatment reduced the activity by 51%. The molecular weight of the bacteriocin was nearly 6 kDa that was quantified using tricine-SDS-PAGE. Our findings suggest that Weissella sp. S3 may be considered a probiotic and useful source of antimicrobial substances in the development of bio-preservatives for food or in MRSA treatment.

• Ocean and Polar Research
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• v.44 no.1
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• pp.29-38
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• 2022

Halophytes are plants that live in harsh environments in coastal regions and are known for their diverse chemical compositions. Limonium tetragonum, a halophyte endemic to Korean shores, is known for its bioactive compounds and is utilized in folk medicine. In this study L. tetragonum extract (LHE) was used to determine and evaluate its anti-osteoporotic properties. Pre-adipocyte and pre-osteoblasts were induced to differentiate along with LHE treatment, and their differentiation was evaluated using differentiation markers. LHE treatment decreased lipid accumulation in 3T3-L1 preadipocytes during adipogenesis. Results indicated that the LHE treatment also decreased the levels of key adipogenic transcription factors: PPARγ, SREBP1c, and C/EBPα. Enhancing osteoblastogenesis by LHE treatment was confirmed in osteoblastogenesis-induced MC3T3-E1 pre-osteoblasts. Cells treated with LHE resulted in increased calcification and alkaline phosphatase (ALP) activity compared with osteoblasts without LHE treatment. Pro-osteogenic and anti-adipogenic effects were also confirmed in D1 murine mesenchymal stromal cells which are capable of differentiation into both adipocytes and osteoblasts. LHE hindered adipogenesis and enhanced osteoblastogenesis in D1 MSCs in a similar fashion. In conclusion, L. tetragonum is believed to possess the potential to be utilized as a nutraceutical ingredient against osteoporotic conditions.

• Journal of Life Science
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• v.20 no.4
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• pp.589-596
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• 2010

We investigated antimicrobial activities of various pine (Pinus densiflora) needle extracts against antibiotic resistant strains of Staphylococcus aureus. Hot water extract showed the highest antimicrobial activity against normal and methicillin resistant Staphylococcus aureus (MRSA), however, it exhibited no antimicrobial activity against penicillin resistant S. aureus (PRSA). Hot water-hexane (HWH), hot water-ethanol (HWE), hexane, and ethanol extracts showed antimicrobial activity against S. aureus, PRSA and MRSA. Minimum inhibitory concentrations (MIC) of HWH, HWE, hexane, and ethanol extracts were 0.05, 0.05, 0.5 and 5 mg/ml, respectively, and HWH and HWE extracts showed the strongest antimicrobial activity among these extracts. Antimicrobial activities of pine needle extracts were stable after heating at $121^{\circ}C$ for 20 min. These results suggested that pine needle extracts can be used as an effective natural antimicrobial agent for food and medical industries.

• Journal of Life Science
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• v.18 no.2
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• pp.287-290
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• 2008

In order to obtain yeast cells producing a bacteriocin, Subpeptin JM4-A or Subpeptin JM4-B, the 48 bp oligonucleotides corresponding to Subpeptin JM4-A and Subpeptin JM4-B genes including codon for start and stop were chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Escherichia coli and Pseudonomas aeruginosa. This result indicates that yeast cells producing Subpeptin JM4-A or Subpeptin JM4-B possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative E. coli and P. aeruginosa cells. The recombinant yeast strains constructed in this study can be applied in the food preservative or. animal foodfeed.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.222-226
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• 2008

The purpose of this study was to investigate the preventive effects of Paeoniae Radix Extract(PRE) against the acute hepatotoxicity-inducing lipopolysaccharide(LPS) in the liver. PRE of 100 mg/kg concentration was intraperitoneally administered into rats at dose of 1.5 ml/kg for 20 days. On day 21, 5 mg/kg of LPS dissolved in saline was injected 4 hours before anesthetization. We examined the levels of glutamate oxaloacetate transaminase(GOT), glutamate pyruvate transaminase(GPT), lactate dehydrogenase(LDH) in serum of rats, superoxide dismutase(SOD) in mitochondrial fractions, and malondialdehyde(MDA), catalase(CAT), glutathione peroxidase(GPx) in liver homogenates. LPS-treatment markedly increased the levels of GOT, GPT, LDH and MDA, and significantly decreased those of SOD, CAT and GPx. But PRE-pretreatment decreased the levels of GOT, GPT, LDH and MDA, by 59.7%, 43.6%, 59.6% and 63.5%, respectively and increased those of SOD, CAT and GPx, by 85.5%, 57.8% and 62.9%, respectively. These results showed that the PRE had the preventive effects against the acute hepatotoxicity-inducing LPS in the liver.