• Journal of Microbiology and Biotechnology
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• 제18권4호
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• pp.759-766
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• 2008

Among more than a hundred colonies of fungi isolated from soil samples, DY-52 has been screened as an extracellular chitin deacetylase (CDA) producer. The isolate was further identified as Mortierella sp., based on the morphological properties and the nucleotide sequence of its 18S rRNA gene. The fungus exhibited maximal growth in yeast peptone glucose (YPD) liquid medium containing 2% of glucose at pH 5.0 and $28^{\circ}C$ with 150 rpm. The CDA activity of DY-52 was maximal (20 U/mg) on the 3rd day of culture in the same medium. The CDA was inducible by addition of glucose and chitin. The enzyme contained two isoforms of molecular mass 50 kDa and 59 kDa. This enzyme showed a maximal activity at pH 5.5 and $60^{\circ}C$. In addition, it had a pH stability range of 4.5-8.0 and a temperature stability range of $4-40^{\circ}C$. The enzyme was enhanced in the presence of $Co^{2+}$ and $Ca^{2+}$. Among various substrates tested, WSCT-50 (water-soluble chitin, degree of deacetylation 50%), glycol chitin, and crab chitosan (DD 71-88%) were deacetylated. Moreover, the CDA can handle N-acetylglucosamine oligomers $(GlcNAc)_{2-7}$.

• Genomics & Informatics
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• 제8권4호
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• pp.185-193
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• 2010

Histone deacetylation and demethylation are epigenetic mechanisms implicated in cancer. Studies regarding the role of modulation of gene expression utilizing the histone deacetylase inhibitor scriptaid and the demethylating agent 5-azacytidine in HL-60 leukemia cells have been limited. We studied the possibility of recovering epigenetically silenced genes by scriptaid and 5-azacytidine in human leukemia cells by DNA microarray analysis. The first group was leukemia cells that were cultured with 5-azacytidine. The second group was cultured with scriptaid. The other group was cultured with both agents. Two hundred seventy newly developed genes were expressed after the combination of 5-azacytidine and scriptaid. Twenty-nine genes were unchanged after the combination treatment of 5-azacytidine and scriptaid. Among the 270 genes, 13 genes were differed significantly from the control. HPGD, CPA3, CEACAM6, LOC653907, ETS1, RAB37, PMP22, FST, FOXC1, and CCL2 were up-regulated, and IGLL3, IGLL1, and ASS1 were down-regulated. Eleven genes associated with oncogenesis were found among the differentially expressed genes: ETS1, ASCL2, BTG2, BTG1, SLAMF6, CDKN2D, RRAS, RET, GIPC1, MAGEB, and RGL4. We report the results of our leukemia cell microarray profiles after epigenetic combination therapy with the hope that they are the starting point of selectively targeted epigenetic therapy.

• 공업화학
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• 제10권1호
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• pp.19-23
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• 1999

아질산염을 이용한 키토산의 부분가수분해 반응에서 반응이 진행됨에 따라서 탈아세틸화도는 감소하였으며 가수분해된 각 fraction에서의 탈아세틸화도는 50% 이하로 확인되었다. GPC를 이용하여 이들 각 유도체의 수평균분자량을 확인한 결과, 물-메탄올에 의한 침전물은 6000에서 4000의 분자량을 가지고 있었으며, 메탄올-아세톤에 의해서는 2000 이하의 분자량을 가지는 것을 얻을 수 있었다. 이때 다분산도는 1.7 이하로 분자량 분포가 좁은 분해물을 얻을 수 있었다. 각 fraction 별로 분자량에 따른 항균효과를 E. coli HB 101과 Bacillus subtilis PP 2에 대해서 시험한 결과 분자량이 5100인 fraction B($H_2O:MeOH=1:5$)가 가장 우수하였고, 모든 시료에서 그람양성균인 Bacillus subtilis PP 2에 대한 항균능이 그람음성균인 E. coli HB 101에 비해 우수하였다.

• 공업화학
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• 제5권5호
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• pp.899-903
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• 1994

게껍질로부터 Hackman법으로 키틴을 추출하였고 키토산은 이것을 일정 온도($100^{\circ}C$)에서 NaOH 용액의 농도와 반응 시간을 변화시켜 각각의 탈아세틸화 정도에 따라 제조하였다. 제조한 시료들은 A=19%, B=52%, C=70% 그리고 D=93%의 탈아세틸화된 것을 사용해 여러 가지 시험을 하였다. 분자량은 탈아세틸화도가 증가함에 따라 감소되는 현상을 나타냈고, 폐수처리 효과에 있어서 SS 제거율은 탈아세틸화도가 증가함에 따라 증가하였고 pH 9에서 우수한 성능을 나타냈으며, COD 제거율은 중성 영역에서 가장 좋게 나타났다.

• BMB Reports
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• 제36권1호
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• pp.95-109
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• 2003

Inflammatory lung diseases are characterized by chronic inflammation and oxidant/antioxidant imbalance. The sources of the increased oxidative stress in patients with chronic inflammatory lung diseases such as asthma and chronic obstructive pulmonary disease (COPD) derive from the increased burden of inhaled oxidants, and from the increased amounts of reactive oxygen species (ROS) generated by several inflammatory, immune and various structural cells of the airways. Increased levels of ROS produced in the airways is reflected by increased markers of oxidative stress in the airspaces, sputum, breath, lungs and blood in patients with lung diseases. ROS, either directly or via the formation of lipid peroxidation products such as 4-hydroxy-2-nonenal may play a role in enhancing the inflammation through the activation of stress kinases (JNK, MAPK, p38) and redox sensitive transcription factors such as NF-${\kappa}B$ and AP-1. Recent evidences have indicated that oxidative stress and pro-inflammatory mediators can alter nuclear histone acetylation/deacetylation allowing access for transcription factor DNA binding leading to enhanced pro-inflammatory gene expression in various lung cells. Understanding of the mechanisms of redox signaling, NF-${\kappa}B$/AP-1 regulation, the balance between histone acetylation and deacetylation and the release and expression of pro- and anti-inflammatory mediators may lead to the development of novel therapies based on the pharmacological manipulation of antioxidants in lung inflammation and injury. Antioxidants that have effective wide spectrum activity and good bioavailability, thiols or molecules which have dual antioxidant and anti-inflammatory activity, may be potential therapeutic agents which not only protect against the direct injurious effects of oxidants, but may fundamentally alter the underlying inflammatory processes which play an important role in the pathogenesis of chronic inflammatory lung diseases.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1203-1210
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• 2011

Function-driven metagenomic analysis is a powerful approach to screening for novel biocatalysts. In this study, we investigated lipolytic enzymes selected from an alluvial soil metagenomic library, and identified two novel esterases, EstDL26 and EstDL136. EstDL26 and EstDL136 reactivated chloramphenicol from its acetyl derivates by counteracting the chloramphenicol acetyltransferase (CAT) activity in Escherichia coli. These two enzymes showed only 27% identity in amino acid sequence to each other; however both preferentially hydrolyzed short-chain p-nitrophenyl esters (${\leq}C_5$) and showed mesophilic properties. In vitro, EstDL136 catalyzed the deacetylation of 1- and 3-acetyl and 1,3-diacetyl derivates; in contrast, EstDL26 was not capable of the deacetylation at $C_1$, indicating a potential regioselectivity. EstDL26 and EstDL136 were similar to microbial hormone-sensitive lipase (HSL), and since chloramphenicol acetate esterase (CAE) activity was detected from two other soil esterases in the HSL family, this suggests a distribution of CAE among the soil microorganisms. The isolation and characterization of EstDL26 and EstDL136 in this study may be helpful in understanding the diversity of CAE enzymes and their potential role in releasing active chloramphenicol in the producing bacteria.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.84-88
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• 2002

The effect of chitosan on the growth of plant pathogenic fungi was investigated. Chitosan solubilized in acetic acid showed much higher and more consistent antifungal activity than that solubilized in HCl. The antifungal activity was not significantly affected within a DA (degree of deacetylation) range of $57.3-99.2\%$ tested. Water-soluble and low molecular weight chitosan ($57.3\%$ DA) against 6 plant pathogens showed that Monosporascus canonballus and Pythium irregulare were the most susceptible to the chitosan, while Fusarium oxysporum and F. graminearum were the most resistant. At a concentration of 2.5 mg/ml, the growth of pathogens was completely inhibited except for F. oxysporum. The $MIC_50$ values varied depending on both the DA of the chitosan and the plant pathogens. A chitosan with $57.3\%$ DA exhibited the lowest $MIC_50$ (ranging <0.1-1.8 mg/ml) and that with $84.7\%$ DA the highest $MIC_50$ (ranging <0.4-4.0 mg/ml) depending on the pathogen.

• Molecules and Cells
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• 제28권6호
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• pp.553-558
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• 2009

In the periphery, a galectin-1 receptor, CD7, plays crucial roles in galectin-1-mediated apoptosis of activated T-cells as well as progression of T-lymphoma. Previously, we demonstrated that $NF-{\kappa}B$ downregulated CD7 gene expression through the p38 MAPK pathway in developing immature thymocytes. However, its regulatory pathway is not well understood in functional mature T-cells. Here, we show that CD7 expression was downregulated by Twist2 in Jurkat cells, a human acute T-cell lymphoma cell line, and in EL4 cells, a mature murine T-cell lymphoma cell line. Furthermore, ectopic expression of Twist2 in Jurkat cells reduced galectin-1-induced apoptosis. While full-length Twist2 decreased CD7 promoter activity, a C-terminal deletion form of Twist2 reversed its inhibition, suggesting an important role of the C-terminus in CD7 regulation. In addition, CD7 expression was enhanced by histone deacetylase inhibitors such as trichostatin A and sodium butyrate, which indicates that Twist2 might be one of candidate factors involved in histone deacetylation. Based on these results, we conclude that upregulation of Twist2 increases the resistance to galectin-1-mediated-apoptosis, which may have significant implications for the progression of some T-cells into tumors such as Sezary cells.

• 분석과학
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• 제8권2호
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• pp.139-159
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• 1995

몇 가지 종류의 corticosteroid에 대하여 액체 크로마토그래피-질량분석법으로 양이온 질량 스펙트럼을 얻었다. 화학구조에 따라 수소 첨가된 분자이온 [$MH^+$], 암모늄 첨가이온 [${MNH_4}^+$], 또는 ($MH^+-60$) 이온이 base peak였고 [$MH^+-18$] 또는 [${MNH_4}^+-18$] 이온 등이 특성적으로 나타났다. Methylprednisolone acetate를 male Sprague-Dawley rat에 경구투여한 다음 24시간 동안 배설된 뇨로부터 유리상태 또는 접합상태의 대사물질들을 가수분해, 추출 및 농축하고, thermospray LC/MS를 사용하여 양이온과 음이온 질량토막이온을 분석하였다. Methylprednisolone acetate의 C-21 위치에서의 탈아세틸화(deacetylation), C-20 위치에서 C=0의 -CHOH로의 환원, C-11 위치에서 CHOH의 C=0로의 산화 또는 C-17과 C-20 사이의 bond cleavage등에 의해 생성되는 것으로 추정되는 10여종의 대사물질을 검출하였다. 그 중에 20-hydroxymethylprednisolone(20-HMP), methylprednisolone(MP), methylprednisone(11-KMP)등은 표준물질과 비교 확인하였다.

• 한국가정과학회지
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• 제1권1호
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• pp.103-112
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• 1998

면직물에 항균성을 부여하기 위하여 패드-건조(-열처리법)에 의해 키토산처리를 하였다. 분자량이 약 50,000으로 비슷하고 탈아세틸화도가 65∼95％인 4종의 키토산과 분자량이 약 1,800이고 탈아세틸화도가 약 86％인 1종의 키토산올리고머를 사용하였다. 키노산올리고머로 처리한 경우에는 세탁내구력을 증진시키기 위하여 가교제 또는 바인더를 가공처리액에 첨가하였다. 항균성은 쉐이크플라스크법에 의해 공시균 Staphylococcus aureus 와 Proteus vulgaris를 사용하여 측정하였다. 세탁내구력은 AATCC Test Method 60-1986 또는 JIS 0217-104에 따라 20회까지 세탁한 후 항균성을 측정하였다. 실험결과, 항균성은 키토산의 농도와 탈아세틸화도가 증가함에 따라 증가하였으며 열처리 유무는 항균성에 큰 영향을 미치지 않았다. AATCC Test Method 60-1986에 따르면 열처리한 시료의 세탁내구력이 열처리하지 않은 시료보다 우수하였다. 가교제나 바인더의 첨가는 키토산올리고머를 처리한 시료의 항균성을 감소시켰으며, JIS 0217-104에 따라 실험한 결과 세탁내구력 향상에 효과가 없었다.