• Korean Journal of Microbiology
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• v.28 no.3
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• pp.229-235
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• 1990

A rapid and sensitive method to detect the extracellular enzymatic activity of bacteria colonies grown on agar plates is described. Selective agar media supplemented with protein, starch, chitin, Tween-80, etc. are conventionally used to detect biochemical properties of bacteria. It has been experimentally demonstrated with bacteria pure cultures that fluorogenic Methylumbelliferyl (MUF)-substrates are excellent substrate analogues for normally occurring polymers. Based on MUF-substrate hydrolysis the new method provides reliable qualitative estimates of extracellular enzymatic properties of bacteria within minutes using pure cultures as well as agar p;ates prepared for colony counts. Extracellular enzyme activities of heterotrophic bacteria from freshwater ecosystems and marine sediment using this method are discussed.

• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1291-1298
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• 2015

Five different polymer nanofibers, namely, polyaniline nanofiber (PANI), magnetically separable polyaniline nanofiber (PAMP), magnetically separable DEAE cellulose fiber (DEAE), magnetically separable CM cellulose fiber (CM), and polystyrene nanofiber (PSNF), have been used for the immobilization of lactase (E.C. 3.2.1.23). Except for CM and PSNF, three polymers showed great properties. The catalytic activities (k_cat) of the free, PANI, PAMP, and magnetic DEAE-cellulose were determined to be 4.0, 2.05, 0.59, and 0.042 mM/min·mg protein, respectively. The lactase immobilized on DEAE, PANI, and PAMP showed improved stability and recyclability. PANI- and PAMP-lactase showed only a 0-3% decrease in activity after 3 months of vigorous shaking conditions (200 rpm) and at room temperature (25℃). PANI-, PAMP-, and DEAE-lactase showed a high percentage of conversion (100%, 47%, and 12%) after a 1 h lactose hydrolysis reaction. The residual activities of PANI-, PAMP-, and DEAE-lactase after 10 times of recycling were 98%, 96%, and 97%, respectively.

• Polymer(Korea)
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• v.32 no.3
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• pp.246-250
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• 2008

Colloidal stability of the biodegradable nanoparticle was characterized by measuring the variation of particle size with time using photon correlation spectroscopy. Three kinds of polymers, namely, poly(D,L-lactide-co-glycolide)(PLGA), PLGA/poly(L-lactide) blends, and PLGA/poly(L-lactide)-g-poly(ethylene glycol) blends were used as matrix material for nanoparticle preparation. Nanoparticles were prepared with or without using poly(vinyl alcohol)(PVA) as suspension stabilizer to evaluate the condition of preparation. Nanoparticles from the blend of amphiphilic graft copolymer with short poly(ethylene glycol) chain and PLGA maintained suspension for 1 day when protein stock solution was introduced. This is somewhat improvement in colloidal stability against protein adsorption compared with that of nanoparticles without PEG moiety. Suspension stabilizer, PVA, had a significant effect on the colloidal stability against freezing and protein adsorption which led to coagulation of nanoparticles. It is important to consider effect of suspension stabilizer as well as materials used to prepare nanoparticle on the colloidal stability.

• Journal of Nutrition and Health
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• v.25 no.6
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• pp.429-449
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• 1992

The consumption of foods rich in TDF should not be associated with impaired mineral absorp-tion and long-term mineral status. In surveys of populations consuming high amounts of TDF e.g Third World populations and vegetarinas gross deficiencies in mineral nutrition have not been noted. If mineral status is low among these groups it is most likely caused by the inadequacy or imbalance of the diet and not by the TDF. The key word is interaction which should be inte-rpreted in dietary imbalances that produce nut-rient deficiencies. There are no strong data to support the concept that TDF inhibits mineral absorption through a binding chelation mechanism. Limited data sug-gest that positively charged groups on polymers such as chitosan and cholestyramine will decrease iron absorption in humans and animals. Because TDF does not contain positively charged groups future research should be directed at the possible role of protein consumed along with TDF and the combination of effects on mineral nutrition Phytic acid is acknowledged as a potent chela-tor of zinc. However its association with zinc and its propensity to lower Zn bioavaiability may enhance the absorption of other elements notably copper and iron. The importance of interactions among nutrients including TDF will gain addi-tional attention in the scientific community. Soluble and insoluble dietary fiber function di-fferently in the intestine. Insoluble fibers accele-rate movement through the intestine. Soluble die-tary fibers appear to regulated blood concentra-tions of glucose and cholesterol albeit by some unknown mechanism. In creased viscosity produ-ced by the SDF in the intestine may provide an explanation of how this class of polymers affects plasma glucose cholesterol and other nutrients. Employing a double-perfusion technique in the rat we demonstrated that viscosity produced by SDF will delay transfer of zinc into the circulatory system. This delayed absorption should not be interpreted as decreased utilization. A great deal of additional research is required to prove the importance of luminaly viscosity produced by SDF on slowing nutrient absorption or regulating bllod nutrient homeostasis. Increased intake of TDF in the total human diet appears desirable. A dietary intake of 35g/day should not be considered to have a negative effect on mineral absorption. It is important to educate people that an intake of more than 35g TDF/day may cause an imbalance in the diet that can adve-rsely affect mineral utilization. Acknowledgments. Appreciation is given to Dr. George V. Vahouny(deceased) who was intense a great competitor in and out of science and who gave the author inspiration Portions of this work were supported by the University of Missouri Ag-ricultural Station and by a grant from the Univer-rch Support Grant RR 07053 from the National Institutes of Health. Contribution of the Missouri Agriculatural Experiments Station Journal Series No. 10747.

• IMMUNE NETWORK
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• v.11 no.3
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• pp.163-168
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• 2011

Background: Nanoparticles (NPs) prepared from biodegradable polymers, such as poly (D,L-lactic acid-co-glycolic acid) (PLGA), have been studied as vehicles for the delivery of antigens to phagocytes. This paper describes the preparation of antigen-loaded PLGA-NPs for efficient cross-priming. Methods: NPs containing a similar amount of ovalbumin (OVA) but different sizes were produced using a micromixer-based W/O/W solvent evaporation procedure, and the efficiency of the NPs to induce the cross-presentation of OVA peptides were examined in dendritic cells (DCs). Cellular uptake and biodistribution studies were performed using fluorescein isothiocyanate (FITC)-loaded NPs in mice. Results: The NPs in the range of $1.1{\sim}1.4{\mu}m$ in size were the most and almost equally efficient in inducing the cross-presentation of OVA peptides via $H-2K^b$ molecules. Cellular uptake and biodistribution studies showed that opsonization of the NPs with mouse IgG greatly increased the percentage of FITC-positive cells in the spleen and lymph nodes. The major cell type of FITC-positive cells in the spleen was macrophages, whereas that of lymph nodes was DCs. Conclusion: These results show that IgG-opsonized PLGA-NPs with a mean size of $1.1{\mu}m$ would be the choice of biodegradable carriers for the targeted-delivery of protein antigens for cross-priming in vivo.

• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.447-459
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• 2003

Generalized 2D correlation spectroscopy has been applied extensively to the analysis of spectral data sets obtained during the observation of a system under some external perturbation. It is used in various fields of spectroscopy including IR, Raman, UV, fluorescence, X-ray diffraction, and X-ray absorption spectroscopy (XAS) as well as chromatography. 2D hetero-spectral correlation analysis compares two completely different types of spectra obtained for a system under the same perturbation. Because of the wide range of applications of this technique, it has become one of the standard analytical techniques for the analytical chemistry, physical chemistry, biochemistry, and so on, and for studies of polymers, biomolecules, nanomaterials, etc. In this paper, we will introduce the principle of generalized 2D correlation spectroscopy and its applications that we have studied.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.722-726
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• 2008

Silica microsphere is a world leading innovative material used in adsorbent packing materials in HPLC technology. The application of microsphere lies in the ability to the surface modification of silica with the special materials such as polymers, metals and bio-active materials. Collagen is a major structural protein of connective tissues and has a good biocompatibility. In this study, we prepared the purified silica porous microsphere, having micro diameters in the range of a pore volume at least 50% by the aggregation procedure of colloidal silica with the polymerization method (PICA). The microspheres were modified by collagen hydrogel to improve the biocompatible properties for biomedical product. The silica/collagen microsphere composite doped with silver nanoparticles was prepared and investigated the capabilities of biomaterial application through the evaluation of the structure characteristics of the microsphere composit.

• Journal of Mushroom
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• v.20 no.3
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• pp.163-167
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• 2022

Bio-based alternative leathers may be produced from biomass fiber, protein polymers, bacterial cellulose, and mushroom mycelia. Of these components, mushroom mycelia are of greatest interest. In this study, the potential of Fomes fomentariusas a mushroom mycelial mat was confirmed, and the optimal strain for the development of the mycelial mat was determined. Moreover, the quality of the mycelial mat was improved by identifying an efficient culture method to increase productivity. Mutant strains whose independence was verified were obtained by treatment with gamma irradiation under various conditions. Biofilm formation by the resulting strains was examined in sawdust and liquid media and the characteristics of the biofilms were analyzed. The biofilm of the mutant strains showed results that were similar to or better than the biofilms of longevity and cypress mushrooms. These findings are expected to be utilized in future research aimed at discovering new biomaterials using mushroom mycelia.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.39-45
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• 2001

Extremophiles are unique microorganisms that are adapted to survive in ecological niches such as high or low temperatures, extremes of pH, high salt concentrations and high pressure. These unusual microorganisms have unique biochemical features which can be exploited for use in the biotechnological industries. Due to the high biodiversity of extremophilic archaea and bacteria and their existence in various biotopes a variety of biocatalysts with different physicochemical properties have been discovered. The extreme molecular stability of their enzymes, membranes and the synthesis of unique organic compounds and polymers make extremophiles interesting candidates for basic and applied research. Some of the enzymes from extremophiles, especially hyperthermophilic marine microorganisms (growth above $85^{\circ}C$), have already been purified in our laboratory. These include the enzyme systems from Pyrococcus, Pyrodictium, Thermococcus and Thermotoga sp. that are involved in polysacharide modification and protein bioconversion. Only recently, the genome of the thermoalkaliphilic strain. Anaerobranca gottschalkii has been completely sequenced providing a unique resource of novel biocatalysts that are active at high temperature and pH. The gene encoding the branching enzyme from this organism was cloned and expressed in a mesophilic host and finally characterized. A novel glucoamylase was purified from an aerobic archaeon which shows optimal activity at $90^{\circ}C$ and pH 2.0. This thermoacidophilic archaeon Picrophilus oshimae grows optimally at pH 0.7 and $60^{\circ}C$. Furthermore, we were able to detect thermoactive proteases from two anaerobic isolates which are able to hydrolyze feather keratin completely at $80^{\circ}C$ forming amino acids and peptides. In addition, new marine psychrophilic isolates will be presented that are able to secrete enzymes such as lipases, proteases and amylases possessing high activity below the freezing point of water.

• KSBB Journal
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• v.24 no.1
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• pp.80-88
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• 2009

Human prostatic acid phosphatase (PAP), with comprehensive homology to glandular kallikrein, are representative serum biomarkers of prostate cancer. Dendritic cell (DC), which is the potent antigen-presenting cells(APC) in the immune system, can induce strong T cell responses against viruses, microbial pathogens, and tumors. Therefore, the immunization using DC loaded with tumor-associated antigens is a powerful method for inducing anti-tumor immunity. The CTP (Cytoplasmic Transduction Peptide) technology developed by Creagene which can transport attached bio-polymers like nucleic acids or proteins into the cell with high permeation efficiency. As the active forms of PAP can mediate apoptotic processing, we used multimer forms of PAP as an inactive form for antigen pulsing of DCs. In this study, multimeric forms of CTP-rhPAP was obtained according to the advanced purification process and subsequently confirmed by gel filtration chromatography, western blot and Dynamic Light Scattering. Therefore, CTP-conjugated PA multimers transduced into the cytoplasm were efficiently presented on the cell surface without any harm effect on cells via MHC class I molecules and result in induction of a large number of effector cell.