• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.76.1-76
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• 2003

The coat protein (CP) of Turnip crinkle virus (TCV) is organized into 3 distinct domains, R domain (RNA-binding) connected by an arm, 5 domain and P domain. We have previously shown that the CP of TCV strongly suppresses RNA silencing, and have mapped N-terminal R domain of which is also the elicitor of resistance response in the Arabidopsis ecotype Di-17 carrying the HRT resistance gene. In order to map the region in the TCV CP that is responsible for silencing suppression, a series of CP mutants were constructed, transformed into Agrobacterium, coinfiltrated either with HC-Pro (the helper component proteinase of tobacco etch potyvirus) known as a suppressor of PTGS or GFP constructs into leaves of Nicotiana benthmiana expressing GFP transgenically. In the presence of HC-Pro, all CP mutants were well protected, accumulating mutant CP mRNAs and their proteins even 5 days post-infiltration (DPI). In the presence of GFP, some mutant constructs which showed the accumulation of CP mutants and GFP mRNAs at early stage but eventually degraded at 5 DPI. Only a mutant which carrying 4 amino acid deletion of R domain was tolerable to maintain suppressing activity, suggesting that the suppressing activity is not directly related with the eliciting activity. A transient assay also revealed that the mutants synthesized their proteins, suggesting that a full length of CP sequences and its intact structure are required to stabilize CP, which suppresses the RNA silencing.

• 미생물학회지
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• 제47권2호
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• pp.158-162
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• 2011

Proteus mirabilis 전사 조절($\underline{P}$roteus $\underline{m}$irabilis $\underline{t}$ranscription $\underline{r}$egulator ) 단백질의 중금속 결합 부위에 대한 아미노산 서열분석에서 PMTR 단백질은 ZntR (아연 저항성) 단백질이 아닌 CueR (구리 저항성) 단백질과 동일한 환경이다. 그리고 겔시프트 법(gel shift assay) 실험에 의하면 PMTR 단백질은 Escherichia coli의 zntA (zinc-translocating P-type ATPase gene) 프로모터에 결합하지 않고 copA (copper-translocating P-type ATPase gene) 프로모터와 Proteus mirabilis에서 atpase (copper-translocating P-type ATPase gene) 프로모터에 결합하였다. DNase I protection 실험에서 PMTR 단백질 결합부위와 DNase I 민감성 염기들이 관찰되었다. P. mirabilis atpase 프로모터에서 민감성 염기로 주형가닥(template strand)에서 C와 A 그리고 비주형가닥(non-template strand)에서 G와 C 염기들이다. 이런 민감성 염기들은 다른 MerR 패밀리 단백질에서 또한 관찰되었으며, 이것은 단백질에 의한 DNA bending을 의미한다.

• BMB Reports
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• 제28권2호
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• pp.112-117
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• 1995

Succinic semialdehyde reductase was inactivated by o-phthalaldehyde. The inactivation followed pseudo-first order kinetics, and the second-order rate constant for the inactivation process was 28 $M^{-1}s^{-1}$ at pH 7.4 and $25^{\circ}C$. The absorption spectrum ($\lambda_{max}$ 337 nm) and fluorescence excitation ($\lambda_{max}$ 340 nm) and fluorescence emission spectra ($\lambda_{max}$ 409 nm) were consistent with the formation of an isoindole derivative in the catalytic site between a cysteine and a lysine residue approximately about 3 $\AA$ apart. The substrate, succinic semialdehyde, did not protect enzymatic activity against inactivation, whereas the coenzyme NADPH protected against o-phthaladehyde induced inactivation of the enzyme. About 1 isoindole group per mol of the enzyme was formed following complete loss of enzymatic activity. These results suggest that the amino acid residues of the enzyme participating in a reaction with o-phthalaldehyde are cysteinyl and lysyl residues at or near the NADPH binding site.

• 한국산업보건학회지
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• 제27권3호
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• pp.193-200
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• 2017

Objectives: This study was performed to evaluate the neurototoxicity of the environmental pollutant lead acetate(LA) and the protective effect of the D-2-amino-5-phosphonovaleric acid(APV), N-methyl-D-aspartate(NMDA) receptor antagonist on LA-induced cytotoxicity in cultured C6 glioma cells. Materials and Methods: For this study, cell viability in cultured C6 glioma cells was assessed by XTT assay and antioxidative effect, such as lactate dehydrogenase(LDH) activity, by LDH detection kit. Results: LA significantly decreased cell viability in a dose-dependent manner, and the XTT50 value was determined to be 33.3 uM of LA. The cytotoxicity of LA was deemed highly toxic according to Borenfreund and Puerner's toxic criteria. The vitamin E antioxidant significantly increased cell viability damaged by LA-induced cytotoxicity in these cultures. For the protective effect of APV on LA-induced cytotoxicity, APV significantly increased not only cell viability, but also inhibition of LDH activity. From these results, it is suggested that oxidative stress is involved in the neurotoxicity of LA, and APV effectively protected against LA-induced cytotoxicity via an antioxidative effect as an inhibotory activity of LDH. Conclusions: Natural resources like APV may be putative therapeutic agents for the toxic diminution of environmental pollutants such as LA correlated with oxidative stress.

• Journal of Life Science
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• 제9권1호
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• pp.26-34
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• 1999

A thermostable pullulanase has been isolated and purified from Thermus caldophilus GK-24 to a homogeneity by gel-filtration and ion-exchange chromatography. The specific activity of the purified enzyme was 431-fold increase from the crude culture broth with a recovery of 11.4%. The purified enzyme showed $M_{r}$ of 65 kDa on denaturated and natural conditions. The pI of the enzyme was 6.1 and Schiff staining was negative, suggesting that the enzyme is not a glycoprotein. The enzyme was most active at pH 5.5. The activity was maximal at $75^{\cire}C$ and stable up to $95^{\cire}C$ for 30 min at pH 5.5. The enzyme was stable to incubation from pH 3.5 to pH 8.0 at $4^{\cire}C$ for 24hr. The presence of pullulan protected the enzyme from heat inactivation, the extent depending upon the substrate concentration. The activity of the enzyme was simulated by $Mn^{2+}$ ion, }$Ni^{2+}$, $Ca^{2+}$, $Co^{2+}$ ions. The enzyme hydrolyzed the ${\alpha}$-1,6-linkages of amylopectin, glycogens, ${\alpha}$, ${\beta}$-limited dextrin, and pullulan. The enzyme caused the complete hydrolysis of pullulan to maltotriose and the activity was inhibited by $\alpha$, $\beta$, or $\gamma$-cyclodextrins. The $NH_{2}$-terminal amino acid sequence [(Ala-Pro-Gln-(Asp of Tyr)-Asn-Leu-Leu-Xaa-ILe-Gly-Ala(Ser)] was compared with known sequences of various sources and that was compared with known sequences of various sources and that was different from those of bacterial and plant enzymes, suggesting that the enzymes are structurally different.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2001년도 International Symposium on Food,Nutrition and Health for 21st Century
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• pp.69-73
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• 2001

Two opioid peptides, YPLDL and YPLDLF, were isolated from enzymatic digests of spinach ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) and named rubiscolin-5 and -6, respectively. These peptides were selective for delta-receptor and the latter was about 3 times more potent than the former. After oral administration in mice at the dose of 100 mg/kg, rubiscolin-6 showed analgesic activity in tail pinch test. It also stimutated learning performance at the same dose in passive avoidance experiment using step-through apparatus. An immunostimulating peptide, MITLAIPVNKPGR, was isolated from a trypsin digest of soybean protein and named soymetide. Immunostimulating activy of soymetide was mediated by fMLP receptor. Interestingly, after oral administration in rats at a dose of 300 mg/kg (po.), soymetide-4 (MITL) protected alopecia (hair-loss) induced by etoposide, a cancer chemotherapy agent. Stimulation of IL-1 release by the peptide was involved in the mechanism. Ovokinin(2-7), RADHPF, is a vasorelaxing peptide released from ovalbumin by the action of chymotrypsin. It lowered blood pressure of spontaneously hypersensive rats (SHR) after oral administration at a dose of 10 mg/kg. RPLKPW, which was designed by replacing 4 amino acid residues in ovokinin(2-7), exhibited hypotensive activity at a dose of 0.1 mg/kg (po.). This peptides was introduced into 3 homologous sites in soybean beta-conglycinin alpha' subunit by site-directed mutagenesis of the cDNA and expressed in E. coli. The minimum effective dose for hypotensive activity of the genetically modified beta-conglycinin alpha' subunit was 10 mg/kg (po.), which is about 1/200 that of ovalbumin.

• BMB Reports
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• 제39권3호
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• pp.253-262
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• 2006

Parkinson's disease (PD) is a common neurodegenerative disorder and is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Although many studies showed that the aggregation of $\alpha$-synuclein might be involved in the pathogenesis of PD, its protective properties against oxidative stress remain to be elucidated. In this study, human wild type and mutant $\alpha$-synuclein genes were fused with a gene fragment encoding the nine amino acid trans activator of transcription (Tat) protein transduction domain of HIV-l in a bacterial expression vector to produce a genetic in-frame WT Tat-$\alpha$-synuclein (wild type) and mutant Tat-a-synucleins (mutants; A30P and A53T), respectively, and we investigated the protective effects of wild type and mutant Tat-$\alpha$-synucleins in vitro and in vivo. WT Tat-$\alpha$-synuclein rapidly transduced into an astrocyte cells and protected the cells against paraquat induced cell death. However, mutant Tat-$\alpha$-synucleins did not protect at all. In the mice models exposed to the herbicide paraquat, the WT Tat-$\alpha$-synuclein completely protected against dopaminergic neuronal cell death, whereas mutants failed in protecting against oxidative stress. We found that these protective effects were characterized by increasing the expression level of heat shock protein 70 (HSP70) in the neuronal cells and this expression level was dependent on the concentration of transduced WT Tat-$\alpha$-synuclein. These results suggest that transduced Tat-$\alpha$-synuclein might protect cell death from oxidative stress by increasing the expression level of HSP70 in vitro and in vivo and this may be of potential therapeutic benefit in the pathogenesis of PD.

• 생명과학회지
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• 제24권12호
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• pp.1356-1363
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• 2014

28개의 아미노산으로 이루어져 있는 Ghrelin은 위 기저부의 X/A-유사 신경내분비 세포에서 주로 합성 분비되는 물질로 음식의 섭취나 비만, 에너지 항상성 등을 조절하는 역할을 하며, 이러한 Ghrelin 활성화는 수용체인 G-protein coupled growth hormone secretagogue receptor-1a (GHS-R1a)와 결합을 통해 일어난다. 최근 보고된 자료에 따르면, ghrelin과 수용체는 위나 시상하부, 뇌하수체 등뿐만 아니라 T 세포나 단핵구 및 대식세포 등 면역 세포에서도 생성되며, 염증반응을 유도하는 사이토카인의 생성을 억제하는 역할을 한다. 또한 흉선의 퇴화 등 면역기관에 있어서도 중요한 호르몬으로 보고되고 있지만 그 기전이나 기능에 대한 연구가 아직 미미한 실정이다. 본 연구에서는 흉선에서 T 세포의 성숙이나 세포활성을 억제하는 물질로 알려져 있는 덱사메타손(Dexamethasone; DEX)으로 세포사멸을 유도시킨 흉선세포에 ghrelin을 처리하여 세포사멸 억제효과를 알아보았다. 그 결과 Ghrelin은 세포사멸에 중요 단백질인 Caspase-3와 PARP 및 Bim의 활성화가 in vivo 및 in vitro 모두에서 효과적으로 저해됨을 확인할 수 있었으며, 이러한 세포사멸의 억제효과는 ghrelin을 처리할 경우 DEX에 의해 활성화된 Glucocorticoid 수용체(GR)의 인산화의 억제와 HSP90 등과 복합체를 이루고 있는 GR이 활성화되면서 분해되는 과정을 억제시켜 결과적으로 핵 안으로 이동하는 과정을 억제하는 기전을 통해 나타남을 알 수 있었다. 이러한 결과 등을 통해 볼 때, ghrelin은 약물이나 체내 생리적 스트레스 등으로 인해 발생하는 흉선 내 면역세포들의 세포사멸에 도움을 줄 것으로 사료되며, 나아가 이로 인한 흉선위축을 보호할 수 있는 치료 후보물질로서의 연구를 기대할 수 있으리라 사료된다.

• Journal of Animal Science and Technology
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• 제48권5호
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• pp.719-726
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• 2006

본 실험은 가수분해 시킨 유청단백질과 Lb. casei HY2782의 세포 추출물을 인간 전립선 세포에처리하여 세포 내 glutathione 농도 상승효과와 산화제 tbutyl hydroperoxide (TBHP)에 의한핵산 손상 방지 효과를 알아보기 위한 실험으로 전립선 세포 RWPE1 cells와 PC3MMM2 cells에 hydrolyzed WPI(500g/m)를 48시간 동안 처리 시, 가수분해 시키지 않은 WPI 보다 각각 28.2%, 38.4%씩 GSH 농도가 증가하는 것을 유의적으로 확인할 수 있었고(p<0.05), 카제인의 경우 RWPE1 cells and PC3MMM2 cells에 처리 시 가수분해 시킨 카제인과의 유의차가 보이지 않았으며 (p<0.05), glutathione 합성저해제인 Buthionine sulfoximin (BSO) 처리 시 Glutathione 농도가 현저하게 낮아지는 것을 확인할 수가 있었다(Anderson, 1998). 전립선 세포 RWPE1 cells 와 PC3MMM2 cells에 Lb. casei HY2782 세포 추출물 처리 시 PC3MMM2 cell에서는 GSH의 농도가 유의적으로 증가하는 것을 확인 할 수 있었고(p<0.05), RWPE1 cell에서는 증가 성향을 확인 할 수가 있었다.가수분해 시킨 유청단백질과 Lb. casei cell 세포추출물 처리 시 산화제에 의한 세포의 DNA 손상 억제정도와 사멸율의 변화를 확인 한 결과, 가수분해 WPI를 처리 후 Oxidant tbutyl hydroperoxide (TBHP)(500mM)를 이용하여 PC3MMM2 세포에 산화적인 스트레스를 주었을 시, TBHP만 처리한 구에서는 62.0%의 생존율을 나타내었고, glutathione 합성저해제인 BSO를 첨가시킨 처리구에서는 33.7%의 생존율을 나타내었다. 가수분해 시킨 WPI와 카제인 처리구에서는 각각 86.7%, 63.6%의 생존율을 나타내었고, WPI와 BSO를 함께 처리한 구에서는 71.5%의 생존율을 나타내었다. 이는 BSO에 의해 GSH의 생성이 저해되어 나타난 결과로 보여지며(Anderson, 1988), 가수분해시킨 WPI 가 가수분해 시킨 카제인보다는 높은 생존율을 나타내는 것을 유의적으로 확인할 수가 있었다. (p<0.05) Lb. casei 세포 추출물처리에 의한 생존율에서는 가수분해시킨 WPI와 유사한 수준의 82.4%의 생존율을 보였다. 가수분해시킨 유청단백질과 Lb. casei cell 세포추출물에 의한 세포에서의 glutathione 농도 증가에 의해 산화제에 의한 DNA의 손상이 적었던 것으로 사료되어지고, 이로 인해 생존율이 높았던 것으로 판단된다.

• 대한약리학회지
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• 제29권1호
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• pp.9-22
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• 1993

허혈성 뇌손상시 칼슘길항제, 항산화제와 산소라디칼 제거제 그리고 흥분성 아미노산 수용체 길항제의 보호효과를 검토하기 위해 본 연구에서는 랫트 뇌 해마조직 절편을 산소와 포도당을 제거한 반응액에 노출시켜 실험적 허혈상태를 유도하였다. 그리고 여러 약물을 처리한 상태에서 허혈시의 뇌세포 손상정도를 생화학적 지표들(절편내 ATP와 반응액내 lactate 및 malondialdehyde (MDA)유리량)을 측정하여 검토하였다. 60분까지 허혈상태를 유발시킨 경우 시간에 따라 절편내 ATP 함량이 감소하였고 lactate 유리량이 증가하였다. 그 후 산소와 포도당이 든 반응액으로 바꿔주니 이들 생화학적 변화들이 회복되는 양상을 보였다. 그러나 본 실험조건에서 허혈상태로부터 완전히 회복되지는 않았다. 동일한 허혈조건에서 verapamil과 비타민 E는 ATP 함량 감소와 절편으로부터의 lactate 유리량의 증가에 대해 보고효과를 보였다. 그리고 verapamil과 diltiazem은 반응액내로의 MDA유리를 감소시켰다. Superoxide dismutase (SOD), glutathione과 MK-801 (NMDA 수용체 길항제)은 20분 허혈조건에서 ATP 함량을 증가시켰으나 그외 다른 조건에서 보호효과를 보이지 않았다. 허혈 후 20분간 산소와 포도당을 재공급한 경우 verapamil은 ATP 함량과 lactate 유리에 보호효과를 보였다. 한편 비타민 E는 20분 허혈 조건에서의 lactate 유리와 60분 허혈시의 MDA 유리 증가에 대해 감소효과를 보였다. 이상의 결과는 칼슘길항제와 비타민 E가 랫트 뇌절편에서의 허혈성 생화학적 손상을 방지함으로 나타난 결과로 해석되며, 칼슘갈항제의 효과가 비타민 E보다 우수함으로 미루어 칼슘길항제는 허혈성 뇌손상에 예방 및 보고효과를 보일 것으로 믿어졌다.