• Journal of Microbiology and Biotechnology
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• v.18 no.4
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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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• v.8 no.4
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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.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.19-23
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• 1999

Chitosan was partially degraded by using nitrous acid. The deacetylation degree of chitosan decreased with its degree of hydrolysis. Deacetylation degree of each fraction was less than 50%. The degraded product was fractionated by means of precipitation using aqueous methanol solution or aqueous methanol-acetone solution. The molecular weight of each fraction was distributed between 6000 and 4000, and below 2000 for being precipitated using aqueous methanol solution and aqueous methanol-acetone solution respectively. They had narrow molecular weight distributions, and their polydispersities were less than 1.7. The antibacterial activities for each fraction were evaluated against Bacillus subtilis HB 101 and E. coli PP 2, gram-positive bacteria and gram-negative bacteria, respectively. Fraction B (Mw=5100) showed high antibacteiral activity. All fractions were more active against Bacillus subtilis than E. coli.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.899-903
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• 1994

Chitin was extracted from crab shell by Hackman method and chitosan was prepared to chitin, that was deacetylated under various concentration of NaOH solution and reaction time at constant temperature, $100^{\circ}C$. Samples were A=19%, B=52%, C=70% and D=93% deacetylation's chitosan and they were tested. When deacetylation was increased, $\overline{Mw}$ was decreased and removal rate of suspended solid and removal rate of chemical oxygen demand were increased. Suspended solid and removal rate of chemical oxygen demand showed the better at pH 9 and pH 7 than any other pH range.

• BMB Reports
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• v.36 no.1
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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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• v.21 no.12
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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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• v.12 no.1
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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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• v.28 no.6
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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.

• Analytical Science and Technology
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• v.8 no.2
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• pp.139-159
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• 1995

Positive ion mass spectra of some corticosteroids were obtained by using liquid chromatography-mass spectrometry(LC-MS). The base peak of each compound showed the protonated molecular ion [$MH^+$], ammonium adduct ion [${MNH_4}^+$] or [$MH^+-60$] ion according to its chemical structure and other characteristic mass ions were [$MH^+-18$], [${MNH_4}^+-18$] and so on. Several rat urinary metabolites of methylprednisolone acetate after the oral administration were detected by the thermospray LC-MS. The identified major metabolites were 20-hydroxymethylprednisolone(20-HMP), methylprednisolone(MP) and methylprednisone(11-KMP), which were supposed to be formed by deacetylation at the position of C-21, reduction at C-20, oxidation at C-11, or due to the bond cleavage between C-17 and C-20.

• Korean Journal of Human Ecology
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• v.1 no.1
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• pp.103-112
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• 1998

Cotton fabric was treated with chitosan by pad-dry(-cure) method to impart antimicrobial properties. Four chitosans of different degree of deacetylation (DAC: 65~95%) with similar molecular weight(MW: ca. 50, 000) and one chitosan oligomer(MW 1, 800, DAC 86%) were used. In order to improve the durability to laundering of antimicrobial activity for the fabrics treated with chitosan oligomer, crosslinker or binder was included in the finishing formulation. Antimicrobial activity against Staphylococcus aureus and Proteus vulgaris was evaluated by the Shake Flask Method. The treated fabrics were laundered up to 20 times according to AATCC Test Method 60-1986 or JIS 0217-104 and antimicrobial activity of the laundered fabrics was evaluated. The antimicrobial activity was increased with the increase of concentration and degree of deacetylation of chitosan. And the cured fabrics showed better durability to laundering than the not-cured fabrics according to AATCC Test Method 60-1986. Crosslinker and binder decreased antimicrobial according of the fabrics treated with chitosan oligomer and were not effective to improve the durability to laundering according to JIS 0217-104. (Korean J Human Ecology 1(1) : 103~112, 1998)