• Korean Journal of Microbiology
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• v.32 no.2
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• pp.147-154
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• 1994

Nuclease was secreted to the environmental media from the Escherichia coli JM107 tranformant harboring the extracellular nuclease gene of Serratia marcescens in the plasmid of pNUC4. Under the growth conditions, the amount of secreted enzyme was increased in parallel with bacterial growth conditions, the amount of secreted enzyme was increased in parallel with bacterial growth. The enzyme was purified using chromatofraphic procedures of Matrex green gel and heparin agarose affinity gel, resulted in 50-fold purification with 15% recovery of the enzyme. The apparent molecular weight of the enzyme was estimated to be 29Kda by sodium dodecylsulfate denaturing gel electrophoresis. Using the purified enzyme, polyclonal antibody was obtained from the rabbit. The specificity of the antibody was confirmed by immunoblotting and immunoprecipitaion. For the investigation of cellular distribution of the enzyme, cells were fractionated into three fractions; cytoplasm, periplasm and extracellular fluid. While more than 80% of the enzymatic activity was detected in the extracellular fluid and periplasm, a little was found in the cytoplasm, indicating that the enzyme was likely to be immediately exported to the membrane for excretion after biosynthesis. These results were confirmed again by immunocytochemistry technique using the antibody.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.19-25
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• 2008

To evaluate the functions of vegetation mat of artificial floating island (AFI) installed in Lake Paldang, nutrients, such as total phosphorus (TP), dissolved inorganic phosphorus (DIP), total nitrogen (TN) and nitrate $(NO_3)$ and microbial factors such as total bacterial numbers, active bacterial numbers and exoenzymatic activities of $\beta$-glucosidase and phosphatase in pore water of medium and bulk lake water were analyzed. The concentration of TN and $NO_3$ in pore water ranged from 4.4 to 7.5mg $L^{-1}$ from 1.2 to 3.8mg $L^{-1}$ respectively, which were ca. 2 times higher than those of lake water. The ranges of TP and DIP of were $1.4\sim4.1mg\;L^{-1}$ and $0.003\sim0.137mg\;L^{-1}$ in pore water of media which were $4\sim25$ and 5 times higher than those of lake water, respectively. The numbers of total bacteria and active bacteria in pore waterwere about 10 times higher than those of laker water. Also, both phosphatase and $\beta$-glucosidase activities of pore water were on an average 10 times higher than those of lake water. These results suggest that the bacteria were playing important role for nutrients concentrating and cycling in media of artificial floating island. And the medium of artificial floating island contained newly created microbial ecosystem, which is responsible for sustaining the growth of macrophytes and the creation of new aquatic ecosystem.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1271-1277
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• 2000

The extracts from tomatoes, apples, carrots, mallows, watercreses+pine needles, Angelica keiskei Koiz, jujubes and lemons were selected and mixed at the ratio of 3 : 3 : 3 : 1/2 : 1/2 : 1/2 : 1/2 : 1/5 on the basis of sensory evaluation. The mixed extracts were divided into three lots and treated as follows. The first lot was heated for 15 sec at $96^{\circ}C$ without centrifugation and filtration, the second filtered through a ultramembrane filter. For the third one, the ultrafiltrate combined with autoclaved retentates on the membrane filter and the previous centrifugal precipitation. The mixed juices were stored in the glass bottles with atmosphere or in film package with nitrogen gas. And then they were stored at $4^{\circ}$ and $20^{\circ}C$. During storage the treated juices showed $pH\;4.07{\sim}4.10$, titratable acidity $66.35{\sim}84.08$, soluble solid $7{\sim}9^{\circ}Brix$, reducing sugar $5.42{\sim}6.97%$, glucose $1.96{\sim}2.30%$ and fructose $3.46{\sim}4.14%$. The ultrafiltered juices showed yellow color, different from orange color of other treatment lots. Peroxidase activity and microbial population were inhibited by thermal treatment and ultrafiltration. The browning effects of the mixed juice of fruits and vegetables during storage were caused by ascorbic acid oxidation and non-enzymatic browning reaction, which could be reduced by change and packing with nitrogen gas instead of atmosphere inside bottles.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.570-577
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• 2021

This study elucidated the biological activities and structural characteristics of polysaccharides isolated from ginseng leaves fermented using Cordyceps sinensis (GLF). GLF comprised at least 18 glycosyl linkages, including 4-linked glucose residues (24.0%). To characterize the neutral polysaccharides in GLF, it was further fractionated by anion exchange chromatography, and the unabsorbed fraction (GLF1) was isolated. Peritoneal macrophages stimulated with GLF1 produced various cytokines in a dose-dependent manner. The properties and activities of the four subfractions (PHI, PHIA1-PHIA3) obtained after sequential enzymatic digestion were examined. PHI and PHIA3 primarily comprised glucose, whereas PHI exhibited an iodine-color reaction. Furthermore, the PHIA1-3 fractions indicated that cytokine production was completely inhibited. These results suggest at the immune activities of GLF1 may be due to the α-(1→4)-glucan branched at the C(O)6 position, which was produced by C. sinensis.

• The Korean Journal of Food And Nutrition
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• v.34 no.5
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• pp.458-467
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• 2021

The effect of 16 cultivars on the quality of the rice porridge was investigated. The 'Geunnun' had the highest water absorption rate, but the 'Segyejinmi' yield (w/w) was the highest. The total sugar content of the rice porridge was 0.29~8.10%, showing significant variation among the cultivars. High amylose 'Dodamssal' and 'Hwaseonchalbyeo' glutinous rice displayed rotational viscosities of <20,000 cP. Rotational viscosities for boiled rice cultivars were 30,000~40,000 cP, representing an intermediate level, and the rotational viscosities of 'Geonyang2' and 'Hanareum4' were over 50,000 cP. These results suggest that the viscosity of rice porridge varies significantly among raw material cultivars. Among other variables affecting the texture profile of rice porridge, there were significant differences in hardness and gumminess among the cultivars. As a raw material, 'Baekokchal', a kind of glutinous rice, is known to be whiter than the non-glutinous rice, but after processing to porridge, it showed the lowest L value (71.1). Starch degrading enzyme activity was not significant in most types of rice porridges within 30 or 60 minutes. Therefore, enzymatic starch degradation is thought to be completed within 30 minutes. Among the tested raw materials, 'Miho' was 73.5 ㎍/mg, indicating the best digestibility in vitro.

• Journal of Forest and Environmental Science
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• v.37 no.1
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• pp.52-61
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• 2021

Decay fungi can decompose plant debris to recycle carbon in the ecosystem. Still, they can also be fungal pathogens, which can damage living trees and/or wood material and cause a large amount of timber loss. We isolated and identified basidiomycetous fungi from the decayed bark of Mongolian oak wrapped with sticky roll traps. The degrading enzyme activities were then tested for all fungal isolates. The decay ability of selected isolates was assessed based on the weight loss of wood discs after inoculating with culture suspension of decay fungi under the different humidity levels. A total of 46 basidiomycetous fungal isolates belonged to 12 species, and 10 genera were obtained from Jong Myo (16 isolates), Chang Kyung palace (7 isolates), Cheong Gye (10 isolates), and Gun Po (13 isolates). Gymnopus luxurians was the most dominant fungus in the present study, and this species distributed in all survey sites with 9 isolates in Jong Myo, followed by 3 isolates in Chang Kyung palace, while Cheong Gye and Gun Po had only 1 isolate each. Among 46 isolates, 44 isolates secreted at least one enzyme, while 25 isolates produced both cellulase and phenol oxidase enzymes, and 2 isolates produced neither. The assessment of decay ability by artificial inoculation indicated that the weight loss of wood discs was significantly influenced by humidity conditions when inoculated with bark decay fungi. The percent weight losses by G. luxurians inoculation in RH of 90-100% and RH of 65-75% were 4.61% and 2.45%, respectively. The weight loss caused by Abortiporus biennis were 6.67% and 0.46% in RH of 90-100% and RH of 45-55%, respectively. The humidity reduction approach should be applied for further studies to control the growth and spread of bark decay fungi on the trunks wrapped with sticky roll traps.

• Journal of Life Science
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• v.32 no.1
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• pp.51-55
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• 2022

Matrix metalloproteinase (MMP) enzymes are responsible for the degradation and formation of the extracellular matrix (ECM), and overproduction of MMPs is observed in several diseases, such as cancer and asthma, that progress with metastatic characteristics. Natural products, especially phytochemicals, have been an important source of MMP inhibitors with reduced side effects. Although the majority of phytochemicals inhibit the enzymatic activity of MMPs, some suppress MMP production. In this context, the current study evaluated the potential of Corydalis heterocarpa, a halophyte with reported bioactivities, to inhibit MMP expression in PMA-stimulated HT-1080 cells. A crude C. heterocarpa extract was shown to decrease the mRNA and protein expression of MMP-2 and MMP-9 while increasing the endogenous MMP inhibitors TIMP-1 and TIMP-2 which regulate MMP expression in healthy tissues. In addition, our results show that the inhibitory effects of C. heterocarpa might occur through suppression of the phosphorylation of MAPK signaling, the upstream activator of MMP overexpression. In conclusion, C. heterocarpa is a potential source of antimetastatic compounds that might serve as lead molecules to develop novel MMP inhibitors.

• Herbal Formula Science
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• v.30 no.2
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• pp.37-44
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• 2022

Objectives : The purpose of this study was to examine the effects of Alisma canaliculatum Extract (ACE) on pacemaker potentials of small and large intestinal interstitial Cells of Cajal (ICC) in mice. Methods : We used enzymatic digestions to dissociate the ICC in the small and large intestine in mice. The whole-cell patch-clamp method was used to record pacemaker potentials in ICC. Results : 1. The ICC generated the pacemaker potentials in small intestine in mice. ACE (0.1-1mg/ml) induced membrane depolarization and decreased frequency with concentration-dependent manners. 2. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, a nonselective cation channel blocker, stopped the small intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE had no effects on the membrane depolarizations in small intestinal ICC. 3. The ICC generated the pacemaker potentials in large intestine in mice. Membrane depolarization appears regularly in the small intestine, but irregularly in the large intestine. ACE induced membrane depolarization (0.1-1mg/ml) and increased frequency (0.1-0.5mg/ml). 4. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, stopped the large intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE depolarized the membrane depolarizations in large intestinal ICC. 5. In mice, intestinal transit rate (ITR) values were dose-dependently decreased by the intragastric administration of ACE. Conclusions : These results suggest that ACE can regulate the pacemaker activity of ICC and the reaction by ACE is different from the small and large intestinal ICC, and the control of the intestinal motion by ACE may be caused by many complex processes.

• Journal of Life Science
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• v.32 no.3
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• pp.256-262
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• 2022

Oxysterols are oxygenated metabolites of cholesterol generated by serial enzymatic reactions during bile acid synthesis. Similar to cholesterol, oxysterols move rapidly to the intracellular region and modulate various cellular processes, such as immune cell responses, lipid metabolism, and cholesterol homeostasis. Different nuclear transcription factors, such as glucocorticoid, estrogen, and liver X receptors, can be modulated by oxysterols in multiple tissues. The most abundant oxysterol, 27-hydroxycholesterol (27-OHC), is a well-known selective modulator that can either activate or suppress estrogen receptor activity in a tissue-specific manner. The contribution of 27-OHC in atherosclerosis development is apparent because a large amount of it is found in atherosclerotic plaques, accelerating the transformation of macrophages into foam cells that uptake extracellular modified lipids. According to previous studies, however, there are opposing opinions about how 27-OHC affects lipid and cholesterol metabolism in metabolic organs, including the liver and adipose tissue. In particular, the effects of 27-OHC on lipid metabolism are entirely different between in vitro and in vivo conditions, suggesting that understanding the physiology of this oxysterol requires a sophisticated approach. This review summarizes the potential effects of 27-OHC in atherosclerosis and metabolic syndromes with a special discussion of its role in metabolic tissues.

• Journal of Appropriate Technology
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• v.5 no.2
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• pp.91-96
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• 2019

Microalgae do not require much land and make a higher efficient oil production. However, it costs still much higher than other biodiesel resources, such as crops. Sugars charge 80% of culture media when microalgae are massively cultured in the fermenter. This study aims to develop a cost-efficient process for sugar production from Chinese cabbage byproducts. Pre-treatment with 0.25% H₂SO₄ was most effective when chopped cabbage was incubated 50℃/130 rpm for 24 hours. To hydrolyze cabbage cellulose, we used cellulases secreted from Trichoderma. harzianum. T. harzianum was cultured at 28℃/pH 7/130 rpm for five days. Optimal enzymatic activity of cellulase was obtained by incubating at 0.24 FPU/ml/45℃/pH 5/130 rpm for three days. In comparison to other agricultural waste, such as rice straw, green tea leaves, and palm residue, Chinese cabbage produced the highest sugar yield. We found the optimal conditions to produce sugar from Chinese cabbage byproducts as a carbon source to culture biodiesel-producing microalgae. The efficient process developed in this study helps microalgae as a sustainable alternative energy source by cost-down.