• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.54-62
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• 2010

A novel harpin-like protein, HpaXm, was described from cotton leaf blight bacteria, Xanthomonas citri subsp. malvacearum. The hpaXm was found to be localized between hrp2 and hrcC. A phylogenetic analysis of the complete amino acid sequence or solely the 13 highly conserved residues $H_2N$-SEKQLDQLLTQLI-COOH in the N-terminal $\alpha$-helix indicates that HpaXm is evolutionarily closer to HpaGXag and HpaXac than to Hpa1Xoo and Hpa1Xoc. A synthesized peptide containing two heptads, 39-LDQLLTQLIMALLQ-52, from the N-terminal a-helical region of HpaXm displayed comparable activity in inducing a hypersensitive response, but two other synthesized derivatives, $HpaXm{\Delta}T44C$ and $HpaXm{\Delta}M48Q$, showed reduced HR-triggering activity. The data from a GST trap test revealed that HpaXm was released into the extracellular medium, hpaXm mutant deficient for the leader peptide (1-MNSLNTQIGANSSFL-15) was unable to be secreted outside cells but still induced HR in tobacco leaves.

• BMB Reports
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• 제31권1호
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• pp.48-52
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• 1998

$p16^{INK4}$, which is a 16-kDa polypeptide protein, inhibits the catalytic activity of the CDK4-cyclinD complex to suppress rumor growth. Both unlabeled and isotope-labeled human tumor suppressor $p16^{INK4}$ protein were overexpressed and purified to characterize biochemical and structural properties. The purified p16 binds to monomeric GST-CDK4 and exists in a monomer conformation for several weeks at $4^{\circ}C$. The circular dichroism (CD) data indicates that p16 contains high percentage of ${\alpha}$-helix and that the helix percentage maximized at pH value of 7.0. One-and two-dimensional nuclear magnetic resonance (NMR) data suggest that purified p16 from our construct has a unique folded conformation under our experimental conditions and exhibits quite stable conformational characteristics.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1429-1433
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• 2006

Application of recombinant protein production and particularly their isotopic enrichment has stimulated development of a range of novel multidimensional heteronuclear NMR techniques. Peptides in most cases are amenable to assignment and structure determination without the need for isotopic labeling. However, there are many cases where the availability of $^{15}N$ and/or $^{13}C$ labeled peptides is useful to study the structure of peptides with more than 30 residues and the interaction between peptides and membrane. CRAMP (Cathelicidin-Related AntiMicrobial Peptide) was identified from a cDNA clone derived from mouse femoral marrow cells as a member of cathelicidin-derived antimicrobial peptides. CRAMP was successfully expressed as a GST-fused form in E. coli and purified using affinity chromatography and reverse-phase chromatography. The yield of the CRAMP was 1.5 mg/l 1. According to CD spectra, CRAMP adopted ${\alpha}$-helical conformation in membrane-mimetic environments. Isotope labeling of CRAMP is expected to make it possible to study the structure and dynamic properties of CRAMP in various membrane systems.

• Preventive Nutrition and Food Science
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• 제8권2호
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• pp.158-161
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• 2003

This study investigated the effects of a ${\gamma}$-irradiated pork (0-30 kGy) diet on lipid peroxidation, cytochrome P-450 content, microsomal glucose 6-phosphatase (G-6-Pase) activity and antioxidative defense systems in diethylnitrosamine (DEN)-induced rat hepatocarcinogenesis. The body weight of rats fed irradiated diets did not change significantly. Liver weight was significantly increased by the administration of DEN, but not by irradiated diets at any dose level. There were no significant effects of gamma irradiation on the content of microsomal malondialdehyde (MDA), cytochrome P-450, or on the activity of G-6-Pase. However, with DEN treatment, cytochrome P-450 content was significantly increased while microsomal G-6-Pase activity was significantly decreased. The ${\gamma}$-irradiated diet supplement did not affect serum retinol or $\alpha$-tocopherol concentrations. However, it did cause a significant decrease in hepatic retinol at 30 kGy. With DEN treatment, hepatic retinol content was even more significantly (p<0.05) decreased compared to the non-irradiated control. The enzyme activities related to antioxidative defense systems, including glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Rx) and glutathione S-transferase (GST) were not affected by gamma irradiation. Those results suggest that an irradiated pork diet up to 30 kGy may not cause a health hazard in experimental animals.

• 한국식품영양과학회지
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• 제31권1호
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• pp.81-86
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• 2002

에탄올 투여에 의한 산화적 손상에 대하여 비타민 A의 보충급여 영향을 조사하고자 흰쥐에게 AIN-76 요구량에 2배 수준으로 retinyl acetate와 $\beta$-carotene을 보충한 식이를 5주간 급여한 후 20% 에탄올 용액(3g/kg B.W)을 급성으로 복강내에 투여하였다. 그런 다음 간조직에서 생성되는 지질과산 화물 함량, 간조직에서의 관련 효소활성도와 항산화비타민의 함량을 분석한 결과는 다음과 같다. 간조직에서의 지질과 산화물 함량은 대조군에 비하여 $\beta$-carotene 공급군에서 유의적인 감소를 나타내었다. 그러나 retinyl acetate 공급군과 $\beta$-carotene 공급군 사이에서의 유의적인 차이를 나타내지 않았다. SOD 활성은 대조군에 비해 retinyl acetate 공급군이 높았고, catalase 활성과 GSH-Px 활성은 실험군 간에 유의적인 차이가 없었다. GST 활성은 에탄올만을 투영한 대조군에 비해 retinyl acetate와 $\beta$-carotene을 공급한 군에서 유의적으로 감소되었다. 간조직 내 retinol 함량은 대조군에 비해 retinyl acetate 공급군에서 유의적으로 높게 나타났으며, 이는 에탄올 급여로 인한 간조직 비타민 A의 소모를 retinyl acetate의 급여로 인해 완화시킨 것으로 여겨진다. 그러나 혈청에서는 실험군 간에 유의적인 차이가 없었다. 간조직내 $\alpha$-tocopherol의 함량은 retinyl acetate와 $\beta$-carotene 공급군에서 증가하는 경향을 나타내었다. 이상의 결과를 종합해 볼 때 금성적인 에탄올의 투여에 대해 retinyl acetate나 $\beta$-carotene을 보충 급여한 경우 항산화효소계 중 superoxide dismutase의 활성이 유도되는 경향을 보였으며, 대표적인 항산화비타민으로 알려진 $\alpha$-tocopherol의 간조직 내 수준이 증가하는 것으로 나타났다.

• 한국균학회지
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• 제30권2호
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• pp.136-141
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• 2002

본 연구는 천마의 성분과 생리활성을 규명하기 위하여 성분분석과 다양한 생리활성 (암세포 생육 저해효능, 항균력, ${\alpha}$-glucosidasege활성 저해효능, angiotensin converting enzyme 저해효능, glutathion S-transferase 활성)을 검토하였다. 천마의 일반성분은 조단백질 5.4%, 조회분 2.6%, 조지방 3.6%, 조섬유 3.3%, 수분 8.1%, 전당이 77%이었으며, 무기질함량은 칼륨(1,150mg/100g) > 인(300mg/100g) 순이었다. 천마추출물의 암세포(간암; Hep3B, 유방암: MCF-7, 폐암; A549, 위암; AGS)에 대한 생육 저해능은 천마추출물 시료농도가 증가함에 따라 증가하는 경향을 보여 1.0mg/ml에서 위암세포(AGS)에 대한 생육 저해능이 83%로 가장 높았다. 천마추출물의 항균활성은 Bacillus subtilis와 Pseudomonas aeruginosa에 대하여 미약한 활성을 나타내었으며, 그 이외의 피검균에 대하여는 항균활성이 거의 없었다. ${\alpha}$-glucosidase효소 활성 저해능은 천마추출물 시료가 1.0mg/ml일때 64%의 높은 저해능을 보였다. ACE활성 저하능은 시료가 $0.2{\sim}1.0mg/ml$의 농도 범위에서 $63{\sim}89%$이었고, 1.0mg/ml일 때 89%로 높은 저해능을 보였다. Glutathion S-transferase(GST) 활성능은 추출물 농도가 1.0mg/ml일 때 221%의 높은 활성을 나타내었다. 이상의 결과로부터 천마는 건강식품이나 기능성 식품의 소재로서 활용이 가능할 것으로 판단되었다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2911-2916
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• 2014

Oxaliplatin is a first-line therapy for colorectal cancer, but cancer cell resistance to the drug compromises its efficacy. To explore mechanisms of drug resistance, we treated colorectal cancer cells (HCT116 and SW620) long-term with oxaliplatin and established stable oxaliplatin-resistant lines (HCT116-OX and SW620-OX). Compared with parental cell lines, $IC_{50}$s for various chemotherapeutic agents (oxaliplatin, cisplatin and doxorubicin) were increased in oxaliplatin-resistant cell lines and this was accompanied by activation of nuclear factor erythroid-2 p45-related factor 2 (Nrf2) and NADPH quinone oxidoreductase 1 (NQO1). Furthermore, luteolin inhibited the Nrf2 pathway in oxaliplatin-resistant cell lines in a dose-dependent manner. Luteolin also inhibited Nrf2 target gene [NQO1, heme oxygenase-1 (HO-1) and $GST{\alpha}1/2$] expression and decreased reduced glutathione in wild type mouse small intestinal cells. There was no apparent effect in Nrf2-/- mice. Luteolin combined with other chemotherapeutics had greater anti-cancer activity in resistant cell lines (combined index values below 1), indicating a synergistic effect. Therefore, adaptive activation of Nrf2 may contribute to the development of acquired drug-resistance and luteolin could restore sensitivity of oxaliplatin-resistant cell lines to chemotherapeutic drugs. Inhibition of the Nrf2 pathway may be the mechanism for this restored therapeutic response.

• Biomolecules & Therapeutics
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• 제4권1호
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• pp.97-102
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• 1996

To investigate whether human $\beta$$_2$-adrenergic receptor devoid of the C-terminal two transmembrane helices retain its ligand binding activity and specificity, 5'780-bp DNA fragment of the receptor gene which encodes amino acid 1-260 of human $\beta$$_2$-adrenergic receptor was subcloned into the bacterial fusion protein expression vector and expressed as a form of glutathione-S-transferase (GST) fusion protein in E. coli DH5$\alpha$. The receptor fusion protein was expressed as a membrane bound form which was verified by SDS-PAGE and Western blot. The fusion protein expressed in this study specifically bound $\beta$-adrenergic receptor ligand [$^3$H] Dihydroalprenolol. In saturation ligand binding assay, the $K_{d}$ value was 7.6 nM which was similar to that of intact $\beta$$_2$-adrenergic receptor in normal animal tissue ( $K_{d}$=1~2 nM) and the $B_{max}$ value was 266 fmol/mg membrane protein. In competition binding assay, the order of binding affinity of various adrenergic receptor agonists to the fusion protein was isoproterenol》epinephrine norepinephrine, which was similar to that of intact receptor in normal animal tissue. These results suggest that N-terminal five transmembrane helices of the $\beta$$_2$-adrenergic receptor be sufficient to determine the ligand binding activity and specificity, irrespective of the presence or absence of the C-terminal two transmembrane helices.s.s.s.

• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1235-1244
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• 2008

Indole-3-acetic acid (IAA) is produced commonly by plants and many bacteria, however, little is known about the genetic basis involving the key enzymes of IAA biosynthetic pathways from Bacillus spp. IAA intermediates from the Gram-positive spore-forming bacterium Paenibacillus polymyxa E681 were investigated, which showed the existence of only an indole-3-pyruvic acid (IPA) pathway for IAA biosynthesis from the bacterium. Four open reading frames (ORFs) encoding indole-3-pyruvate decarboxylase-like proteins and putative indole-3-pyruvate decarboxylase (IPDC), a key enzyme in the IPA synthetic pathway, were found on the genome sequence database of P. polymyxa and cloned in Escherichia coli DH5$\alpha$. One of the ORFs, PP2_01257, was assigned as probable indole-3-pyruvate decarboxylase. The ORF consisted of 1,743 nucleotides encoding 581 amino acids with a deduced molecular mass of 63,380 Da. Alignment studies of the deduced amino acid sequence of the ORF with known IPDC sequences revealed conservation of several amino acids in PP2_01257, essential for substrate and cofactor binding. Recombinant protein, gene product of the ORF PP2_01257 from P. polymyxa E681, was expressed in E. coli BL21 (DE3) as a glutathione S-transferase (GST)-fusion protein and purified to homogeneity using affinity chromatography. The molecular mass of the purified enzyme showed about 63 kDa, corresponding closely to the expected molecular mass of IPDC. The indole-3-pyruvate decarboxylase activity of the recombinant protein, detected by HPLC, using IPA substrate in the enzyme reaction confirmed the identity and functionality of the enzyme IPDC from the E681 strain.

• 천문학회보
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• 제44권1호
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• pp.53.2-53.2
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• 2019

$H{\alpha}$ surges (i.e. cool/dense collimated plasma ejections) may act as a guide for a propagation of magnetohydrodynamic waves. We report a high-resolution observation of a surge observed with 1.6m Goody Solar Telescope (GST) on 2009 August 26, from 18:20~UT to 18:45UT. Characteristics of plasma motions in the surge are determined with the normalizing radial gradient filter and the Fourier motion filter. The shape of the surge is found to change from a 'C' shape to an inverse 'C' shape after a formation of a cusp, a signature of reconnection. There are apparent upflows seen above the cusp top and downflows below it. The upflows show rising and rotational motions in the right-hand direction, with the rotational speed decreasing with height. Near the cusp top, we find a transverse oscillation of the surge, with the period of ~2 min. There is no change of the oscillation phase below the cusp top, but above the top a phase change is identified, giving a vertical phase speed about 86kms-1. As the height increases, the initial amplitude of the oscillation increases, and the oscillation damping time decreases from 5.13 to 1.18min. We conclude that the oscillation is a propagating kink wave that is possibly excited by an x-point oscillation.