• Polymer(Korea)
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• v.25 no.2
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• pp.160-167
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• 2001

The various compositions of polyimide (PI)/polyamideimide (PAI) composites were prepared by heat treatment of the solvent cast PI precursors/PAI blends. The optical micrographs showed that a good compatibility was observed between poly(amic acid) (PAA) and PAI, but in the case of PAME/PAI mixtures, a phase separation apparently occurred due to the absence of ionic and/or H-bonding forces. Regardless of PI precursors, the similar tensile properties were observed. The tensile modulus of the composites were higher than that of the neat polyimide. The X-ray diffraction patterns of the composites showed that the chain rearrangement of PI was increased due to the plasticizing effect of PAI, which has lower glass transition temperature than that of PI, during thermal imidization process.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.222-231
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• 1989

Three classes of proteinase inhibitors are known in soybean; the Kunitz trypsin inhibitor (SKTI), the Bowman-Birk proteinase inhibitor and its isoinhibitors. To study the molecular structure and expression characteristics of the SKTI, antibody was obtained by immunizing rabbit with the SKTI purified from soybean by preparative electrophoresis. Anti-SKTI antibody was not only specific for mature SKTI in soybean seed but also recognized the precursor which was synthesized in vitro. Translation in vitro was carried out in wheat germ extract with polyadenylated mRNA isolated from developing soybean seeds. One of the seed specific translation products, MW 24K, was identified to be the precursor for the SKTI by immunoprecipitation with anti-SKTI antibody. Mature SKTI of MW 20K, however, was not detected in the translates in vitro. These results suggest that the precursor polypeptide is synthesized from the mRNA and is cleaved to yield mature SKTI in soybean seed. The SKTI gene was expressed with the maturation of soybean seed in a tissue-specific and development stage-specific manner.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.89-93
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• 2016

In this study, we investigated the separation behavior of the anticancer agent paclitaxel and its semi-synthetic precursor 10-deacetylpaclitaxel (10-DAP) from plant cell cultures. As a result of sequential separation/purification performed by biomass extraction with solvent, liquid-liquid extraction, adsorbent treatment, hexane precipitation, and fractional precipitation, the adsorbent treatment was found to be the most effective in separating and recovering 10-DAP from paclitaxel. The optimal adsorbent type, crude extract/adsorbent ratio, and adsorbent treatment temperature were sylopute, 1:1.5 (w/w), and $20^{\circ}C$, respectively. The separation/recovery of 10-DAP from paclitaxel was 74.1% in adsorbent treatment process under optimal conditions.

• Journal of Animal Science and Technology
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• v.49 no.5
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• pp.593-598
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• 2007

The current study was undertaken to determine the effects of sex steroid hormones(estrogen, testosterone and 19-nortestosterone) on differentiation and proliferation of pig preadipocytes. The preadipocytes were isolated from the backfat of new-born female pigs by collagenase digestion. 10－8M and 10－7M sex steroid hormones were treated to the cultured preadipocytes. Sex steroid hormones treated during the early stage of cell growth did not affect differentiation and proliferation of preadipocytes. However, testosterone and 19- nortestosterone treated during the late stage of cell growth stimulated differentiation of pig preadipocytes.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.138-138
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• 1993

인슈린 유사체를 유전공학적 방법으로 생산하여 새로운 당뇨병 치료제로써의 가능성을 타진한다. 인슈린 B 사슬의 C 말단 아미노산 codon을 threonine 대신을 methionine을 지령하도록 하고 여기에 인슈린 A사슬을 지령하는 염기를 바로 부착시켜, 이를 대장균에서 발현시키므로써 외사슬 인슈린 선구체를 제조하고, 이를 분리 정제한 다음 취화브롬 으로 절단하므로서 ($B^{30}$-homoserine) 인슈린을 제조한다. 1. 외사슬 인슈린 전구체 유전자를 합성한 후 대장균의 발현 운반체내 e-galactosidase 유전자와 융합시켜 도입하므로서 재조합된 융합단백질을 생산하였다. 2. 재조합 대장균을 발효한 후 urea 융합단백질을 분리하고 DEAE-Sephacel과 Sephadex G-200을 이용하여 순수 정제하였다.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.283-290
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• 1988

A spontaneous revertant of mutation rbsB103 that is ribose taxis-positive was characterized. This revertant was found to be export-competent in the export of ribose-binding protein shown by the disappearance of accumulated mutant precursor protein and the export of mature ribose-binding protein to the periplasm. The reversional change was shown to be in the region of risB gene that codes for the amino terminal portion of ribose-binding protein. Analysis by high-performance liquid chromatography of peptide patterns of ribose-binding proteins confirmed the relationship between the wild-type and the revertant proteins as shown for the mutant previously (Iida et al., 1985). When the processing rate of presursor proteins from the wild type and the revertant strain in vivo was compared by pulse-chase experiment, it was found that processing is less efficient than normal in the revertant. Purified mature proteins from both wild-type and revertant were subjected to amino acid sequencing. The results confirmed the amino acid changes deduced from the DNA sequencing and showed that processing of the revertant precursor occured in the correct position even though there are two different amino acids present in the signal sequence.

• Journal of Sericultural and Entomological Science
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• v.30 no.2
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• pp.96-104
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• 1988

Vitellin, the major yolk protein of the silkworm, Bombyx mori was pruified, and its immunological properties and the quantitative changes during embryogenesis were studied. The ovary transplantation into male hosts was also carried out to find its effect on the yolk protein synthesis. The pupal vitellogenin and the egg vitellin of Bombyx mori were purified by DEAE-cellulose column chromatography. These two female specific proteins showed the same mobility in the polyacrylamide gel electrophoresis and the same reaction in the double immunodiffusion test. The immunological identity was also observed between the vitellins of Bombyx mori and Bombyx mandarina. The rudimentary ovaries transplanted into the male hosts of silkworms produced eggs without vitellin, indicating that the yolk precursors synthesized in other female organ beyond the ovary were necessary to produce vitellins. The major yolk protein, vitellin was disintegrated and utilized mostly during late stage of embryogenesis. It was different characteristics from the egg specific protein, which was utilized continuously from the early embryonic stage.

• Journal of Animal Science and Technology
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• v.55 no.1
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• pp.19-23
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• 2013

The current study was carried out to determine the effects of Kohlrabi (Brassica oleracea var. gongylodes) on proliferation and differentiation of pig preadipocytes and $_3T_3-L_1$ cells. Pig preadipocytes were isolated from the backfat of the new-born pigs. Twenty-four hours after seeding, the cells were washed with DMEM/F-12 (designated day 0). To measure the cell proliferation, the cells were treated with 25 ng/ml and 100 ng/ml ethanol extracts of Kohlrabi (peel and flesh) for two days (day 0 ~ 2). To measure differentiation, the cells were treated with Kohlrabi for two days (day 0 ~ 2) and cell differentiation was measured on day 6. Twenty-five ng/ml and 100 ng/ml of Kohlrabi peel decreased proliferation of pig preadipocytes by 4.59% and 17.7%, respectively, compared with the control and Kohlrabi flesh by 11.4% and 19.2%, respectively. However, Kohlrabi did not inhibit cell differentiation. To measure the effects of Kohlrabi on proliferation and differentiation of $_3T_3-L_1$ cells, the cells were treated with Kohlrabi for two days in culture, like pig preadipocytes. Kohlrabi (both peel and flesh) did not show any effects on cell proliferation and differentiation. In summary, the results of the current study showed that Kohlrabi decreased proliferation of pig preadipocytes, but no inhibitory effects on differentiation of the cells. Kohlrabi had no effects on proliferation and differentiation of $_3T_3-L_1$ cells.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.31-31
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• 1993

지금까지 내유기용매성 분리막의 소재로는 Polysulfone이 많이 사용되었으나 내유기용매성이 고도로 요구되는 분야에는 적합하지 않았다. 이의 해결을 위해서 Polyimide를 소재로한 분리막의 개발에 대한 연구가 많이 진행되고 있다. 그러나 Polyimide는 내열성, 내유기용매성 등이 우수한 반면 T$_g$가 높고 용해되지 않아서 가공하는데 많은 제약이 있는 단점을 가지고 있다. 또한 기존에 널리 사용되었던 2단계 합성방법, 즉 Polyimide 전구체인 Polyamic acid를 합성하고 이를 casting하여 film을 얻은 뒤 다시 고온으로 열처리하여 Polyimide를 제조하는 방법은 공정이 번거롭고 부분적으로 불용성을 나타내기도 하였다. 본 연구에서는 1단계 용액 증합법으로 용융성 Polyimide를 합성하여 이를 소재로 내유기용매성 분리막을 제조하였다. 1단계 중합벙는 Polyamic acid를 합성하고 이를 film으로 만드는 공정이 필요치 않으며, 공정이 비교적 간단하고 경제적으로 유리한 잇점이 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.943-945
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• 2013

The study of Schwann cell myelination has been facilitated by the availability to isolate and establish pure population of primary Schwann cells. Dorsal root ganglia (DRG) of mouse embryo as source of Schwann cells were used in this study. This method includes three steps: first step of dissociation of the embryonic DRG, second step of expansion of Schwann cell precursors, followed by mechanical separation of the Schwann cell-neuronal network from the underlying fibroblasts, and third step of purification of Schwann cells from the associated neurons and subsequent expansion of the purified Schwann cells. We made a highly purified population of Schwann cells and Schwann cell-neuron networks in a short period using this procedure.