• 한국식품과학회지
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• 제20권1호
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• pp.106-111
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• 1988

미강단백질을 식용화하기 위한 기초연구를 목적으로 산화, 환원제처리 및 인산화가 분리탈지미강단백질의 품질 및 기능성에 미치는 영향을 조사하였다. 산화, 환원제를 처리한 분리단백은 알카리처리구보다 필수아미노산 함량이 높았고, 색상, pepsin소화성이 양호하였으며 용해도, 용적밀도, 유화성 및 유화안정도 등이 개선되었다. pH 10.5, $35^{\circ}C$에서 STMP(sodium trimeta phosphate)로 분리탈지미강단백을 3시 간 반응시켜 인산화하였다. 인산화한 분리단백의 단백가는 55이었으며 용해도, 수분흡착도, 유화성과 유화안정도 및 기포성과 포립안정도등의 기능성이 향상되었으나 색상, 소화성, 용적밀도 및 지방흡착도는 인산화의 효과가 나타나지 않았다.

• 한국잠사곤충학회지
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• 제51권1호
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• pp.15-19
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• 2013

작잠은 가잠과는 종속이 다른 섬유 곤충으로 우수한 섬유용 재료를 만든다. 최근 비섬유용 소재로 작잠 견단백질을 활용하기 위한 기초 연구의 일환으로 작잠 견단백질을 용해 조건에 대하여 연구 결과 작잠견사의 연감율은 16.8%로 나타났으며, 작잠견사는 염화칼슘 에탄올 혼합 용매에는 용해되지 않으나 질산칼슘수화물의 용융액에는 용해되었다. 질산칼슘과 에탄올의 조성비를 조정하여 낮은 농도의 질산칼슘 농도에서도 작잠견사가 용해되었다. 작잠 실크단백질의 주요 아미노산 조성은 알라닌, 글리신, 세리신으로 작잠 정련사와 유사한 조성을 보였다. 따라서, 금후 작잠 견단백질의 적절한 용해시스템 확보 및 소재개발을 위한 기초 자료로 활용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.595-600
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• 1998

In order to investigate a relationship of the structure-antifungal and hemolytic activities between cecropin A(1-8)-magainin 2(1-12) and cecropin A(1-8)-melittin(1-12) hybrid peptides, several analogues with amino acid substitution at positions 10 (Ile) and 16 (Ser) were designed and synthesized. The increase of the hydrophobicity by substituting with Leu, Phe, and Trp at position 16 in cecropin A(1-8)-magainin 2(1-12) did not have a significant effect on antifungal activity but caused a remarkable increase in hemolytic activity. These results indicate that the hydrophobic property at position 16 of cecropin A(1-8)-magainin 2(1-12) is more correlated to hemolytic activity than to antifungal activity. Replacement with Pro at position 10 of cecropin A(1-8)- magainin 2(1-12) and cecropin A(1-8)-melittin (1-12) caused a remarkable decrease in a-helical contents in the 50% TFE solution and induced a reduction in lytic activity against Aspergillus flavus, and Aspergillus fumigatus. These results demonstrate that flexibility at the central hinge region is essential for lytic activity against fungal cells and $\alpha$-helicity of the peptides.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1001-1010
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• 2005

Bacillus megaterium KL39, an antibiotic-producing plant growth promoting rhizobacterium (PGPR), was selected from soil. The antifungal antibiotic, denoted KL39, was purified from culture filtrate by column chromatography using Dion HP-20, Silica gel, Sephadex LH-20, and prep-HPLC. Thin layer chromatography, employing the solvent system of ethanol:ammonia:water=8:1:1, showed the $R_{f}$. value of 0.32. The antibiotic KL39 showed a negative reaction with ninhydrin solution, positive with iodine vapor, and also positive with Ehrlich reagent. It was soluble in methanol, ethanol, butanol, and acetonitrile, but insoluble in chloroform, toluene, hexane, ethyl ether, or acetone. Its UV spectrum had the maximum absorption at 208 nm. Amino acid composition, FAB-mass, $^{1}H-NMR,\;^{13}C-NMR$, and atomic analyses showed that the antibiotic KL39 (MW=1,071) has a structure very similar to iturin E. The antibiotic KL39 has a broad antifungal spectrum against a variety of plant pathogenic fungi including Rhizoctonia solani, Pyricularia oryzae, Monilinia froeticola, Botrytis cinenea, Altenaria kikuchiana, Fusarium oxysporum, and F. solani. An MIC value of $10\;{\mu}g/ml$ was determined for Phytophthora capsici. Macromolecular incorporation studies with P. capsici using radioactive [$^{3}H-adenine$] as the precursor, indicated that the antibiotic KL39 strongly inhibits the DNA biosynthesis of the fungal cell. Microscopic observation of the antifungal action showed abnormal hyphal swelling of P. capsici. The purified antibiotic KL39 was very effective for the biocontrol of in vivo Phytophthora-blight disease of pepper.

• Asian Pacific Journal of Cancer Prevention
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• 제15권3호
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• pp.1299-1306
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• 2014

Background: Nano-biotechnology is recognized as offering revolutionary changes in various fields of medicine. Biologically synthesized silver nanoparticles have a wide range of applications. Materials and Methods: Silver nanoparticles (AgNPs) were biosynthesized with an aqueous extract of Pterocladiella (Pterocladia) capillacea, used as a reducing and stabilizing agent, and characterized using UV-VIS spectroscopy, Fourier Transform Infra red (FT-IR) spectroscopy, transmission electron microscopy (TEM) and energy dispersive analysis (EDX). The biosynthesized AgNPs were tested for cytotoxic activity in a human hepatocellular carcinoma ($HepG_2$) cell line cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, 1% antibiotic and antimycotic solution and 2 mM glutamine. Bacterial susceptibility to AgNPs was assessed with Staphylococcus aureus, Bacillus subtilis [Gram+ve] and Pseudomonas aeruginosa and Escherichia coli [Gram-ve]. The agar well diffusion technique was adopted to evaluate the bactericidal activity of the biosynthesized AgNPs using Ampicillin and Gentamicin as gram+ve and gram-ve antibacterial standard drugs, respectively. Results: The biosynthesized AgNPs were $11.4{\pm}3.52$ nm in diameter. FT-IR analysis showed that carbonyl groups from the amino acid residues and proteins could assist in formation and stabilization of AgNPs. The AgNPs showed potent cytotoxic activity against the human hepatocellular carcinoma ($HepG_2$) cell line at higher concentrations. The results also showed that the biosynthesized AgNPs inhibited the entire panel of tested bacteria with a marked specificity towards Bacillus subtillus. Conclusions: Cytotoxic activity of the biosynthesized AgNPs may be due to the presence of alkaloids present in the algal extract. Our AgNPs appear more bactericidal against gram-positive bacteria (B. subtillus).

• Journal of Pharmaceutical Investigation
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• 제25권2호
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• pp.109-116
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• 1995

For the administration of narcotic antagonist with short half-life and low patient compliance, the sustained release system using biodegradable matrix is effective. Polyphosphazenes are of considerable interest as biodegradable matrix systems for controlled release of drugs. In this study, biodegradable polyphosphazenes available for the sustained release implantable device were synthesized, and their application was examined. Poly[dichlorophosphazene] was synthesized by solution polymerization method and confirmed with IR spectrum. Poly[bis(ethyl glycinate) phosphazene] and poly[ (diethyl glutamate)-co-(ethyl glycinate)phosphazene] were then produced by substitution of amino acid alkyl esters for chloride side groups. Using these polymers, the implantable devices of 1 mm thickness and $10{\times}10\;mm$ size containing naloxone hydrochloride were prepared and their release and degradation profiles were measured. In the case of poly[bis(ethyl glycinate)phosphazene] with swelling characteristics, degradation rate was slower than the release rate, showing that the release rate is partly dependent on the swelling rate. In contrast, the degradation rate of polyl[(diethyl glutamate)-co-(ethyl glycinate)phosphazene] matrix was identical with release rate of naloxone hydrochloride. On the basis of these results, it is expected that these polymers can be applied to sustained release implantable systems delivering narcotic antagonist.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.56-62
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• 2000

The hpa gene genetically linked to the ctxa2b gene was cloned into the pTED expression vector, and the constructed pTEDhpa/ctxa2b was transformed into Excherichia coli. The fusion protein, the adhesin fused to the cholera toxin subunit A2B (CTXA2B) subunit, was expressed to high levels as inclusion bodies in E. coli. The expressed protein was partially purified by washing the inclusion bodies with working solution containing 8M Urea and 0.1M DTT. Refolding of denatured fusion protein was carried out in the presence of glutathione redox buffer. The refolded fusion protein was purified by size exclusion chromatography. The expressed fusion protein was verified by SDS-PAGE, western blotting with antibodies to both antigenic components of adhesin and cholera toxin subunit B (CTXB), and its N-terminal amino acid sequence was analyzed. The orderly assembled fusion protein was confirmed by modified Gm1-ganglioside ELISA with Abs to adhesin. The results indicate that the purified fusion protein is an Adhesin/CTXA2B protein containing the H. pylori adhesin and $G_{m1}4-ganglioside binding activity of CTXB and the expressed fusion protein in E. coli could be easily purified by the refolding process, Its molecular weight was 168kDa as estimated by size exclusion chromatography. The Adhesin/CTXA2B protein may be used as a candidate antigen for oral immunization against H. pylori.

• The Korean Journal of Physiology
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• 제22권2호
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• pp.219-230
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• 1988

The effect of glycine, structurally the most simple amino acid was investigated on the electrophysiological characteristics of the isolated superfused atrial muscle and sinus node cells of the rabbit heart. Superfusion of the sinus node cell with glycine solution (3, 5 and 8 mM) produced concentration-dependent increments of OS (overshoot potential) and MDP (maximum diastolic potential). Generally action potential amplitude increased as a result of greater increment of OS than that of MDP. The changes in action potential of the sinus node cell peaked in $7{\sim}10{\;}minutes$ after onset of superfusioin. On the contrary to the response to intravenously administered glycine, the rate of spontaneous firing of sinus node cell was invariably increased following superfusion with glycine. Action potential duration manifested as $APD_{60}$ (time to 60% repolarization) was significantly shortened by glycine. And the electrophysiological effects of glycine on the atrial muscle cell were similar to that on the sinus node cells. The results of present study suggest that glycine can exert direct effects on the atrial muscle and sinus node cells of the rabbit heart.

• 대한화학회지
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• 제30권2호
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• pp.145-151
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• 1986

3-CN, 4-CN, $3-NH_2$ 및 $4-NH_2$ 치환피리딘의 해리상수를 온도(15 ∼ 40${\circ}C$)와 압력(1-2500bar)을 변화시키면서 측정하였다. 측정방법은 전도도법을 적용했으나 낮은 해리상수를 가진 물질에서도 적용되는 피리딘류의 염용액의 전도도를 측정하므로 계산가능한 방법을 모색하여 응용하였다. 이 방법은 어떤 조건에서의 해리상수를 알고 있어야 하는 것과 실험값을 외삽하여 피리딘염의 전도도를 알아야 하는 번거로움도 있으나 측정이 가능하다는 것을 확인할 수 있다. 이들 치환체의 해리상수는 온도가 증가하면 커지고 압력이 높아지면 해리상수는 작아진다는 것을 알 수 있었다. 또 반응의 열역학적 성질을 계산하여 반응성도 고찰하였다.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.484-488
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• 1988

토양분리균 Pseudomonas sp.가 생산하는 inulinase를 분리.정제하여 얻은 단일 단백질 효소 PI과 PII는 탄수화물 함량이 각각 15%와 2.4%인 당 단백질 형태의 endo-inulinase로서 두 효소가 모두 촉매활성에 필수적인 tryptophan 잔기를 가지고 있었다. 분자량은 PI 210,000, PII 170,000으로 측정되었다. 1mM pCMB 존재에 의해 두 효소가 약80% 정도의 활성저해를 보였으나 5mM cysteine 또는 1mM dithiothreitol을 첨가하면 효소활성이 거의 완전 회복되는 특성을 나타내었다. 최종 가수분해산물인 fructose(1mM)에 의해 PI, PII 효소가 각각 15% 정도의 활성저해를 받는 반면 Co$^{+2}$ 이온은 50~60%의 높은 활성화 효과를 보였다. 두 효소는 pH 4.0~7.5사이에서 매우 안정하였으며, 열에 대하여서도 비교적 안정하여 6$0^{\circ}C$, 120분 가열에 의해 PI이 약 27%, PII가 약 40%의 실활을 나타낼 뿐이다. 또한 60units의 효소를 사용, 2% inulin을 5$0^{\circ}C$에서 72시간 가수분해 시켰을 때 PI약 70%, PII약56%의 기질 분해율을 보였다.