• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.60-61
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• 1996

Polyanion-polycation complexes had been known for a long time on an empirical basis fromthe mutual precipitation of proteins, before Kossel at the end of the previous century recognized the electrostatic nature of the interaction between oppositely charged polyions. The formation of polyelectmlyte complexes is essentially a result of the electrostatic nature of the interaction between oppositely charged polyions. This interaction in the macroscopic homogeneous system the phase transition by polysalt precipitation as well as the chemical and physical structure of polyelectrolyte complex membranes have been intensively investigated from the themodynamical and kinetical point of view.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.271-272
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• 2002

Newcastle disease virus (NDV) vaccines were produced from Vero cells by using lively attenuated virus strain. The MOI of 0.1.' serum concentration of 2%. initial pH of 8.0. and infection time of 3 days were found to be optimum conditions for vaccine production. The treatment of polycation enhanced the virus production. When ascorbic acid was added as an antioxidant, NDV production was also enhanced. Utilization of $CaCl_2$ showed an inhibitory effect on the propagation of NDV. It was also found the ammonium ion concentration higher than 4mM inhibited virus production. Thus ammonium ion removal system was tried for the efficient production of NDV vaccine.

• Plant Resources
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• v.8 no.2
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• pp.87-90
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• 2005

In tobacco, in vitro pollination has been successfully applied to overcome interspecific incompatibility. The use of this technique will make it possible to introduce DNA into pollen tubes just before fertilization. In this study, we showed improvement of the efficiency of in vitro self-pollination and introduction of foreign genes into pollen tubes by the method of polycation. A plasmid harbouring the GUS gene was introduced into pollen grains and pollen tubes, which had incubated on pollen germination medium(PGM), by polyornithine method. Transient expression of the GUS in pollen grains and pollen tubes that were treated with 0, 2, 5 and $10{\mu}g/m\ell$ DNA was observed. In results, combination of the techniques of polyornithine and in vitro pollination was efficient new technique for genetic transformation through fertilization processes.

• Journal of Life Science
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• v.21 no.5
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• pp.693-699
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• 2011

Spermidine is a ubiquitous polycation that is synthesized from putrescine, which serves as a precursor of spermine. In recent years, spermidine was found to be a polyamine that plays an important role in longevity. Reactive oxygen species (ROS) such as hydroxyl radical, superoxide and hydrogen peroxide have been shown to be involved in various pathogenic processes as well as aging. The direct scavenging effect of spermidine on DPPH radical, $H_2O_2$ and hydroxyl radical, and its protective effect against DNA oxidation related to oxidative stress were evaluated in vitro. It was observed that spermidine exhibits scavenging activities on DPPH radical and H2O2 above 500 ${\mu}M$. Spermidine was especially effective in exerting a scavenging activity on hydroxyl radical. In addition, spermidine at 1000 ${\mu}M$ showed a clear protective effect against DNA oxidation. Furthermore, the expression level of anti-oxidant enzymes such as superoxide dismutase in humam dermal fibroblasts increased in the presence of spermidine compared with blank group. These results suggest that spermidine can be used as an antioxidant to prevent ROS-related diseases including inflammation, cancer and aging.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.58-58
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• 1993

Pervaporation has become important as a method to separate liquid mixtures, sepecially azeotropic and close boiling-point mixtures. Especially, water-alcohol separations have been carried out a lot because of the practical interests in the industries. However, outstanding membranes with high selectivity and high permeability have not been available in common use yet. In order to separate selectively out the water mixed with alcohols with an aim of the purification of the alcohols, a membrane has tO have excellent affinity to water. Among the hydrophilic polymers, polyacrylic acid and poly(vinyl alcohol) are used widely. In recent years, ionomers and polyion complexes, better hydrophitic materials, start to be used. The polyion complex membranes, consisting of polyacrylic acid (PAA) and polycation, showed excellent permeation rates and selectivities. It was known that among the polycations, ioneries, which have quaternary ammonium groups in the backbone chain, were more effective in giving membranes of higher permselectivities. On this base, syntheses and characterizations of the polycations, with different chemical structures from the published ones, for the polyion complex membrane formation were studied in this paper.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.842-846
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• 2008

Layer-by-layer assembled multilayers of poly(ethersulfone)s were deposited on the surface of Nafion membrane for the application of direct methanol fuel cells (DMFC). Aminated poly(ethersulfone) (APES) and sulfonated poly(ethersulfone) (SPES) were used as a polycation and a polyanion for fabrication of the multilayer films. UV/Vis absorption spectroscopy verified a linear build-up of the multilayers of APES and SPES on the surface of Nafion. Thin multilayer films deposited on the Nafion membrane enabled methanol permeability of the membrane to decrease by 78% in comparison with the pristine Nafion. The performance of DMFCs in concentrated methanol was highly enhanced by using the multilayer modified Nafion.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.179-183
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• 2004

A biocompatible polyelectrolyte complex multilayer (PECML) film consisting of poly-L-lysine (PLL) as a polycation and hyaluronic acid (HA) as a polyanion was developed to test its use for surface modification to prevent cell attachment and protein drug delivery. The formation of PECML through the electrostatic interaction of HA and PLL was confirmed by contact angle measurement, ESCA analysis, and HA content analysis. HA content increased rapidly up to 8 cycles for HA/PLL deposition and then slightly increased with an increasing number of deposition cycle. In vitro release of PLL in the PECML continued up to 4 days and ca. 25% of HA remained on the chitosan-coated cover glass after in vitro release test for 7 days. From the results, PECML of HA and PLL appeared to be stable for about 4 days. The surface modification of the chitosan-coated cover glass with PECML resulted in drastically reduced peripheral blood mononuclear cell (PBMC) attachment. Concerned with its use for protein drug delivery, we confirmed that bovine serum albumin (BSA) as a model protein could be incorporated into the PECML and its release might be triggered by the degradation of HA with hyaluronidase.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.586-590
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• 2019

The aim of this study was to fabricate a dextran polyelectrolyte multi-layer on a bare metal stent (BMS) and to evaluate bio-physical properties of the layer. Diethylaminoethyl-dextran (DEAE-D) as a polycation and dextran sulfate (DS) as a polyanion were successively coated on the bare metal stent by a well-known layer-by-layer procedure. The morphology of the stent surface and its cell adhesion were studied after each coating step by scanning electron microscopy. The stent showed more blotched and slightly rougher morphology after dextran-DS coating. The contact angle of the DEAE-DS group ($39.5{\pm}0.15^{\circ}$) was significantly higher than that of the BMS group ($45.16{\pm}0.08^{\circ}$), indicating the improvement of hydrophilic. The SMC proliferation inhibition in the DEAE-DS-coated stent group ($20.9{\pm}0.04%$) was stronger than that in the control group ($21.7{\pm}0.10%$ in DS-coated group only). The DEAE-DS coating is desired for stent coating materials with biocompatibility and anti-restenosis effect.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.438-442
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• 1997

Antisense oligonucleotide represents an interesting tool for selective inhibition of gene expression. However, their low efficiency of introduction within intact cells remains to be overcome. Antisense-$TGF{\beta}$ (25 mer) and antisense-$TGF{\beta}$ (18 mer) were used to study the cellular transport and biological function of antisense oligonucleotide in vitro. Since TGF and TNF play on important role in regulating the nitric oxide production from macrophages, the action of the above antisense oligonucleotides was easily monitored by the determination of nitrite. Poly-L-lysine, benzalkonium chloride and tetraphenylphosphonium chloride were used as polycations, which neutralize the negative charge of antisense oligonucleotide. The production of nitric oxide mediated by .gamma.-IFN in mouse peritoneal macrophage was increased by antisense-TGF.betha. in a dose-dependent manner. Antisense-$TGF{\beta}$ reduced the nitric oxide release from activated RAW 264.7 cells. Significant enhancement in the nitric oxide production was investigated by the cotreatment of poly-L-lysine with antisense-$TGF{\beta}$On the meanwhile, inhibition effect of antisense-$TGF{\beta}$ is not changed by the addition of poly-L-lysine. These results demonstrate that control of expression of $TGF{\beta}$ and TNF.alpha. gene is achieved using antisense technology and the cellular uptake of antisense oligonucleotide could be enhanced by ion-pairing.

• BMB Reports
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• v.31 no.3
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• pp.221-226
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• 1998

Phosphorylation of phytochrome may play important functional roles to control plant photomorphogenesis. Many attempts have failed to identify the protein kinase that phosphorylates phytochrome in vivo. It has been reported that a polycation-stimulated protein kinase activity was associated with the purified phytochrome. However, it is not known if the kinase activity is an intrinsic property of phytochrome or whether it comes from a contaminant of the purified phytochrome. In the present study, three protein kinases that phosphorylate phytochrome have been identified from etiolated oat seedlings. A polycationstimulated protein kinase that had very similar enzymatic properties with that associated with the purified phytochrome was identified in the cytosolic extract. It phosphorylated several contaminant proteins in the kinase preparation as well as phytochrome and had a broad substrate specificity. A CK II-type protein kinase phosphorylated phytochrome and the exogenously added casein. It is likely that this kinase may not be a feasible candidate for the kinase phosphorylating phytochrome in vivo since the content of the kinase seemed to well exceed the content of phytochrome in the etiolated oat seedlings. Another protein kinase that had unique enzymatic properties phosphorylated phytochrome very specifically and seemed to be present in a small quantity in the etiohlted seedlings. It is expected that one of three kinases may be responsible for the phytochrome phosphorylation in vivo.