• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.129-136
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• 2006

Although cleaner and cheaper deinking of ONP could be performed at the neutral or low alkaline condition excessive loss from froth-flotation is unavoidable and so reduction of alkali or caustic soda dosage sacrifices recycling yield. Now the new trade-off regarding alkali dosage versus flotation yield is urgently required in order to set the optimized neutral or low alkaline deinking process of ONP. Lipase from Thermomyces Lanuginosus has an effect on desizing and deacetylation reaction and it could be applied to the stock of pre flotation secondary stage in order to reduce the flotation reject without the sacrifice of optical properties of flotation accepts. Instead of inorganic base, lipase could be applied as a biochemical catalyst for the selective modification of valuable hydrophobic particles in deinking stock, for example cellulose fines and inorganic fillers covered by hydrophobic additives or contaminants. When the enzymatic hydrolysis of ester bond could be made on the surface of hydrophobic particulates, unwanted float of fine particles could be prevented. Now the enhancement of flotation selectivity or the modification of the hydrophobicity of deinking stock is expected to be promoted by the enzymatic pre treatment. And the reduction of recycling cost with the saves of raw material, recovered paper would be possible as a result.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.1
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• pp.18-24
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• 2001

The advantage of using Streptomyces griseus HUT 6037 in the production of chitinase or chitosanase is that the organism is capable of hydrolyzing amorphous or crystalline chitin and chitosan according to the type of the substrate used. We investigated the effects of the enzyme induction time and chitin sources, CM-chitosan and deacetylated chitosan (degree of deacetylation 75-99%), on production of chitosanase. We found that this strain accumulated chitosanase when cells were grown in the culture medium containing chitosanaceous substrates instead of chitinaceous substrates. The highest chitosanase activity was obtained at 4 dyas of cultivation with 99% deacetylated chitosan. The specific activities of chitinase and chitosanase were 0.91 and 1.33 U/mg protein at 3 and 5 days, respectively. From the study of the enzymatic digestibility of various degrees of deacetylated chitosan, it was found that (GlcN)$_3$, (GlcN)$_4$and (GlcN)(sub)5 were produced during the enzymatic hydrolysis reaction. The results of this study suggested that the sugar composition of (GlcN)$_3$was homogeneous and those of (GlcN)$_4$and (GlcN)(sub)5 were heterogeneous.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1090-1094
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• 2006

Histone acetylation modification is one key mechanism in the regulation of gene activation. In this study, we investigated the global levels of histone H4 acetylation of insulin like growth factor I (IGF1) and growth hormone (GH) genes in the lungs of two somatic cell cloned calves. Data showed the levels of histone H4 acetylation of IGF1 and GH genes vary widely within different gene regions, and, in almost all regions of the two genes, acetylation levels are lower in the aberrant clone than in the normal clone. Thus we suggest that inefficient epigenetic reprogramming in the clone may affect the balance between acetylation and deacetylation, which will affect normal growth and development. These findings will also have implications for improvement of cloning success rates.

• Toxicological Research
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• v.32 no.1
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• pp.35-46
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• 2016

No-flow ischemia occurs during cardiac arrest, hemorrhagic shock, liver resection and transplantation. Recovery of blood flow and normal physiological pH, however, irreversibly injures the liver and other tissues. Although the liver has the powerful machinery for mitochondrial quality control, a process called mitophagy, mitochondrial dysfunction and subsequent cell death occur after reperfusion. Growing evidence indicates that reperfusion impairs mitophagy, leading to mitochondrial dysfunction, defective oxidative phosphorylation, accumulation of toxic metabolites, energy loss and ultimately cell death. The importance of acetylation/deacetylation cycle in the mitochondria and mitophagy has recently gained attention. Emerging data suggest that sirtuins, enzymes deacetylating a variety of target proteins in cellular metabolism, survival and longevity, may also act as an autophagy modulator. This review highlights recent advances of our understanding of a mechanistic correlation between sirtuin 1, mitophagy and ischemic liver injury.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.88-89
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• 2000

Chitosan is derived from chitin by deacetylation in the presence of alkali, which is a copolymer consisting of $\beta$-(1longrightarrow4)-2-acetamido-D-glucose and $\beta$-(1longrightarrow4)-2-amino-D-glucose units with the latter usually exceeding 80% (Arvanitoyannis et al., 1998). Chitosan has been developed as new physiological material since it possesses antibacterial activity, hypocholesterolemic activity and antihypertensive action. However, even though chitosan has very strong functional properties in many areas, its high molecular weight and high viscosity may restrict the use in vivo. In addition, there is little doubt that such properties will influence absorption in the human intestine. Recently, studies on chitosan have attracted interest for converted chitosan to oligosaccharide, because the oligosaccharide possesses not only water-soluble property but also versatile functional properties such as antitumor activity, immune-enhancing effects, enhancement of protective effects against infection with some pathogens in mice, antifungal activity, calcium absorption accelerating effect (Jeon et al., 1999) and antimicrobial activity. There is, however, little information on the toxicity of chitosan oligosaccharide. (omitted)

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.6-10
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• 1995

Chitin was prepared from Solenocera prominentis by deproteinization pretreatment of Neutrase. The optimal enzyme concentration of neutrase, pH, and temperature on deproteinization were 3.0 mg/ml, pH 6.0 and $50^{\circ}C$ as indicated by the minimum protein remaining on the chitin. The residual protein, the degree of deacetylation, Ca and P content in chitin prepared from Solenocera prominentis were similar with commercial chitin. The molecular weight was $1.2{\times}10^{8}$ dalton and the yield of chitin was 25.8%.

• YAKHAK HOEJI
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• v.26 no.1
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• pp.1-8
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• 1982

Derivation of triterpenoids and then the screening for corticomimetics among them is our primary interest. $C_{11}$-oxo-triterprenoids except glycyrrhetinic acid are rarely found in the plant kingdom. Based on the facts that $C_{3}$ and $C_{11}$-Oxo-group are essential for the corticoid-like-activity through its competitive inhibition on the corticoid-5.betha.-reductase, it was attempted to produce artificial inhibitor on the enzyme by introducing $C_{11}$-oxo group to the triterpenoids of oleanene series such as oleanolic acid and hederagenin. We could obtain the $C_{11}$-oxo-oleanolic acid m.p. $264-6^{\circ}$, uv ${\lambda}max$ 249 and $C_{11}$-oxo-hederagenin amorp. uv ${\lambda}max$ 251 by acetylation, $CrO_{3}$-oxid., and deacetylation. Glycyrrhetinic acid, a natural 11-oxo-compound and the other 11-oxo-derivatives of oleanolic acid and hederagenin were compared in their inhibitory activity on the corticoid-5.betha.-reductase. The inhibitory activity of those compound were decreased in the order of $C_{11}$-oxo-oleanolic acid, $C_{11}$-oxo- hederagenin, glycyrrhetinic acid. This suggests more strong corticomimetic activity of those artificially derived $C_{11}$-oxo-oleanolic acid and $C_{11}$-oxa-hederagenin. Their Ki value were $4.6{\times}10^{-4}M$ and $5.8{\times}10^{-4}M$ respectively.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.113-118
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• 2021

Chitosan is a polysaccharide derived from chitin by deacetylation. Chitosan is non-toxic, biodegradable, and biocompatible, so that it can be used in wide variety of medical applications such as wound healing and antimicrobial biomaterials. It also used as dermal fillers due to its ability to inject with liquid formulations. For investigation on in vivo distribution of these chitosans, Bolton-Hunter-conjugated chitosan (Chitosan-BH) was synthesized by the reaction between the primary amino group of chitosan and N-hydroxysuccinimide ester group of Bolton-Hunter reagent. Then Chitosan-BH was radiolabeled with ¹²⁵I (Chitosan-BH-¹²⁵I) using a Chloramine-T method. The effects of each radiolabeling step on the radiolabeling yield of the final product were tested. The results showed that purification step had significant effects on the radiolabeling yield of the final product. Finally, SPECT/CT images were obtained to evaluate in vivo uptake of the radiolabeled chitosan (Chitosan-BH-¹²⁵I) in several organs. The highest uptake was found in the site of injection at 21 days post-injection. The results of this study suggest that chitosan is expected to be useful for biomaterials of dermal fillers.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.6
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• pp.533-540
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• 2023

Sweroside is a natural monoterpene derived from Swertia pseudochinensis Hara. Recently, studies have shown that sweroside exhibits a variety of biological activities, such as anti-inflammatory, antioxidant, and hypoglycemic effects. However, its role and mechanisms in high glucose (HG)-induced renal injury remain unclear. Herein, we established a renal injury model in vitro by inducing human renal tubular epithelial cell (HK-2 cells) injury by HG. Then, the effects of sweroside on HK-2 cell activity, inflammation, reactive oxygen species (ROS) production, and epithelial mesenchymal transition (EMT) were observed. As a result, sweroside treatment ameliorated the viability, inhibited the secretion of inflammatory cytokines (TNF-α, IL-1β, and VCAM-1), reduced the generation of ROS, and inhibited EMT in HK-2 cells. Moreover, the protein expression of SIRT1 was increased and the acetylation of p65 NF-kB was decreased in HK-2 cells with sweroside treatment. More importantly, EX527, an inhibitor of SIRT1, that inactivated SIRT1, abolished the improvement effects of sweroside on HK-2 cells. Our findings suggested that sweroside may mitigate HG-caused injury in HK-2 cells by promoting SIRT1-mediated deacetylation of p65 NF-kB.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2503-2508
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• 2013

Histone deacetylation mediated by histone deacetylases (HDACs) has been reported as one of the epigenetic mechanisms associated with tumorigenesis. The poor responsiveness of anticancer drugs found with cholangiocarcinoma (CCA) leads to short survival rate. We aimed to investigate mRNA expression of HDACs class I and II, and the effect of HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and valproic acid (VPA), in CCA in vitro. Expression of HDACs was studied in CCA cell lines (M213, M214 and KKU-100) and an immortal cholangiocyte (MMNK1) by semi-quantitative reverse transcription-PCR. SAHA and VPA, as well as a classical chemotherapeutic drug 5 -fluorouacil (5-FU) were used in this study. Cell proliferation was determined by sulforhodamine assay. $IC_{50}$ and $IC_{20}$ were then analyzed for each agent and cell line. Moreover, synergistic potentional of VPA or SAHA in combination with 5-FU at sub toxic does ($IC_{20}$) of each agent was also evaluated. Statistic difference of HDACs expression or cell proliferation in each experimental condition was analyzed by Student's t-test. The result demonstrated that HDACs were expressed in all studied cell types. Both SAHA and VPA inhibited cell proliferation in a dose-dependent manner. Interestingly, KKU-100 which was less senstitive to classical chemotheraoeutic 5-FU was highly was sensitive to HDAC inhibitors. Simultaneous combination of subtoxic doses of HDAC inhibitors and 5-FU signiicantly inhibited cell proliferation in CCA cell lines compared to single sgent treatment($P{\leq}0.01$), while sequentially combined treatments were less effective. The present study showed inhibitory effects of HDACIs on cell proliferation in CCA cell lines, with synergistic antitumor potential demonstrated by simultaneous combination of VPA or SAHA with 5-FU, suggesting a novel alternative therapeutic strategy in effective treatment of CCA.