• 대한의생명과학회지
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• 제12권1호
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• pp.17-22
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• 2006

The baculovirus expression system is a powerful method for producing large amounts of the human erythrocyte-type glucose transport protein, heterologously. Characterization of the expressed protein is expected to show its ability to transport sugars directly. To achieve this, it is a prerequisite to know the properties of the endogenous sugar transport system in Spodoptera frugiperda Clone 21 (Sf21) cells, which are commonly employed as a host permissive cell line to support the baculovirus replication. The Sf21 cells can grow well on TC-100 medium that contains 0.1% D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transport system. However, unlike the human glucose transport protein that has a broad substrate and inhibitor specificity, very little is known about the nature of the endogenous sugar transport system in Sf21 cells. In order to characterize further the inhibitor recognition properties of the Sf21 cell transporter, the ability of phloretin, cytochalasin B and D-fructose to inhibit 2-deoxy-D-glucose (2dGlc) transport was examined by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. The 2dGlc transport in the Sf21 cells was very potently inhibited by phloretin, the aglucone of phlorizin with a $K_i$ similar to the value of about $2{\mu}M$ reported for inhibition of glucose transport in human erythrocytes. However, the Sf21 cell transport system was found to differ from the human transport protein in being much less sensitive to inhibition by cytochalasin B (apparent $K_i$ approximately $10\;{\mu}M$). In contrast, It is reported that the inhibitor binds the human erythrocyte counterpart with a $K_d$ of approximately $0.12\;{\mu}M$. Interestingly, the Sf21 glucose transport system also appeared to have high affinity for D-fructose with a $K_i$ of approximately 5mM, contrasting the reported $K_m$ of the human erythrocyte transport protein for the ketose of 1.5M.

• 한국환경복원기술학회지
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• 제25권6호
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• pp.13-24
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• 2022

The purpose of this study is to evaluate the applicability of Ecosystem Service Matrix method in Songnisan and Hannamgeumbukjeongmaek Boeun-gun area. The assessment was carried out with 25 land cover types by 7 ecosystem values. The research area was divided by 30m x 30m cell unit and the each cell value was classified into 5 grades. The total number of cell under the investigation was 433,910 units in Songnisan and 84,975 in Boeun-gun. Class I and II area were widely spread and Class V area is narrowly distributed inside of Class III area in Songnisan. I area, II area and separately managed zone belong to Ecological Zoning map and Environmental Conservation Value Assessment Map(Environment + Ecology) were assessed Class I in Ecosystem service matrix. In conclusion, Ecosystem Service Matrix assessment based on land cover map is a rapid assessment methodology which reflecting ecosystem functions in a larger area. If it is supported with more ecosystem functions, the more precise nature value can be calculated.

• 한국식품영양과학회지
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• 제33권2호
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• pp.271-277
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• 2004

최근에 방사선 조사에 대해 방호효과를 가지는 것으로 알려진 보중익기탕의 골수세포 분화 유도 효과에 대해 관찰하였다. 시험관에서 골수세포를 배양했을 때, 배양시간(5일,10일)에 따라 대조군의 세포 수는 현저히 감소하였고, 보중익기 탕의 total 분획을 첨가하였을 때도 비슷한 결과를 얻었다. 그러나 polysaccaride 분획을 첨가하였을 때는 감소하는 세포수가 일정한수준에서 유지되며 더 이상 감노하지 않았다. 그리고 이들 세포가 어떤 종류의 세포인지를 유세포분석기로 분석한 결과, Pre-B세포의 특징적인 세포 표면 단백질인 CDl9와 CD40을 동시에 발현한 세포인 것이 확인되었다. 또한, 이들 세포는 분화과정 이 끝난 B세포가 분비하는 IgM 뿐만 아니라 IgG1, G2a, G3를 분비하였다. 이상의 결과 보중익기탕의 polysaccaride 분획에 골수세포가 B세포로 분화 증식하는 것을 유도하는 성분이 포함되어 있어 방사선 조사로 상해를 입은 조혈계에 대한 방호 효과를 나타내는 것으로 생각된다.

• 한국가금학회지
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• 제19권3호
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• pp.161-176
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• 1992

콕시듐병은 감수성이 있는 숙주의 장에 주로 감염된 Eimeria에 의하여 일어나는 것으로 가축과 가금의 성장과 사료이용에 막대한 해를 미친다. Eimeria속에 속하는 원충은 주로 세포내에 기생하며 무성생식과 유성생식을 거쳐야 하는 매우 복잡한 생활사를 가진다. Eimeria에 대한 백신개발은 주로 방어면역의 기전과 백신에 사용될 수 있는 항원을 찾는 방면으로 활발한 연구가 이루어지고 있다. 원충은 질병 본래의 모습이나 전파방법이 독특하므로 원충성 질병의 방제에 있어서는 이러한 점이 충분히 숙고되어야 할 것이다. 난해하고 복잡한 세포나 세포 분비물질간의 작용은 콕시듐병의 병성기전 뿐 아니라 방어 면역의 형성에도 매우 깊이 관여하고 있다. 따라서, Eimeria의 감염에 따른 방어기전을 충분히 이해하는 것이 가장 좋은 백신을 개발하는 첩경이 될 것이다.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1090-1096
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• 2006

O-Methylation is a common modification reaction found in nature, and is mediated by an O-methyltransferase (OMT). OMTs have been mainly studied in plants, whereas only a few OMTs have been studied in microbes. When searching the Bacillus cereus genome, four putative small molecular OMTs were identified, among which BcOMT-1 was cloned and expressed in E. coli as a his-tag fusion protein. The whole cell expressing BcOMT-1 was used to methylate several flavonoids. Eriodictyol, luteolin, quercetin, and taxifolin, all of which contain 3' and 4' hydroxyl groups, served as methyl group acceptors for BcOMT-1, whereas naringenin, apigenin, 3,3'-dihydroxyflavone, and 3,4'-dihydroxyflavone did not function as substrates. Analysis of the reaction products using HPLC showed two different peaks, and NMR revealed that the methylation position was at the hydroxyl group of either carbon 3' or 4'. Therefore, this showed that BcOMT-1 used flavonoids containing ortho hydroxyl groups and transferred a methyl group to either of two hydroxyl groups.

• Biomolecules & Therapeutics
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• 제24권2호
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• pp.191-198
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• 2016

The vitamin D receptor (VDR) is a member of the nuclear receptor (NR) superfamily. The VDR binds to active vitamin $D_3$ metabolites, which stimulates downstream transduction signaling involved in various physiological activities such as calcium homeostasis, bone mineralization, and cell differentiation. Quercetin is a widely distributed flavonoid in nature that is known to enhance transactivation of VDR target genes. However, the detailed molecular mechanism underlying VDR activation by quercetin is not well understood. We first demonstrated the interaction between quercetin and the VDR at the molecular level by using fluorescence quenching and saturation transfer difference (STD) NMR experiments. The dissociation constant ($K_d$) of quercetin and the VDR was $21.15{\pm}4.31{\mu}M$, and the mapping of quercetin subsites for VDR binding was performed using STD-NMR. The binding mode of quercetin was investigated by a docking study combined with molecular dynamics (MD) simulation. Quercetin might serve as a scaffold for the development of VDR modulators with selective biological activities.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.383-391
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• 2014

Biotin-S-S-Phosphine was designed and synthesized as a potential tool for a proteomic study of O-GlcNAcmodified proteins. This reagent features a disulfide linker between a triarylphosphine moiety, which allows selective conjugation to azide-containing proteins, and a biotin moiety that can allow easy isolation through its strong affinity toward avidin-coated solid beads. The disulfide linkage within this reagent can allow the easy release of the bound molecules of interest, which is difficult to achieve when a biotin:avidin pair is used alone, by reducing the disulfide bond of the reagent with DTT. Preliminary in vitro biological assays with azidelabeled and unlabeled cell lysates and a pure protein Nup62 showed that the Biotin-S-S-Phosphine reagent is highly reactive toward the free thiol groups of proteins. When a molecular tool with a disulfide linker is applied to the enrichment of the molecules of interest from other species, it is important to block the free-thiols of the sample using exhaustive alkylation prior to the Staudinger ligation reactions to restore the bioorthogonal nature of this reaction.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1297-1306
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• 1998

Carotenoids are yellow to orange red pigments that are ubiquitous in the nature and its annual pro duction amounts to one hundred million ton. This review discussed physicochemical properties, antiox idative activity, anticancer activity of carotenoids and its production technology. Carotenoids, mainly used as food colourants, are characterized by its strong reactive conjugated double bonds, related to oxidation by heat, light, acid, and metal ions. The provitamin A activity of carotenoids is higher in trans form than in cis form. Antioxidative properties of carotenoids are related to ionone structure and long, conjugated polyene chain number. In particular, carotene, astaxanthin, canthaxanthin, and lycopene possess strong antioxidant activity, compared with tocopherol. Especially, carotene, astaxanthin, carotene, fucoxanthin, halocynthiaxanthin and peridinin impart strong anticancer activity against lung cancer, breast cancer, buccal pouch cancer and nerve cell cancer. Carotene and astaxanthin are produced by biotechnology using algae such as Dunaliella salina and Haematococcus pluvalis. But the change of cultivation conditions and screening of algae, efficiently producing carotenoids, are needed for its commercial production. Carotenoids are expected to be used in the various fields through explanation of its biological activity and establishment of commercial production technology.

• 천문학회보
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• 제44권1호
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• pp.49.1-49.1
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• 2019

Giant radio relics in the outskirts of galaxy clusters have been observed and they are interpreted as synchrotron emission from relativistic electrons accelerated via diffusive shock acceleration (DSA) in weak shocks of Ms < 3.0. In the DSA theory, the particle momentum should be greater than a few times the momentum of thermal protons to cross the shock transition and participate in the Fermi acceleration process. In the equilibrium, the momentum of thermal electrons is much smaller than the momentum of thermal protons, so electrons need to be pre-accelerated before they can go through DSA. To investigate such electron injection process, we study the electron pre-acceleration in weak quasi-perpendicular shocks (Ms = 2.0 - 3.0) in an ICM plasma (kT = 8.6 keV, beta = 100) through 2D particle-in-cell simulations. It is known that in quasi-perpendicular shocks, a substantial fraction of electrons could be reflected upstream, gain energy via shock drift acceleration (SDA), and generate oblique waves via the electron firehose instability (EFI), leading the energization of electrons through wave-particle interactions. We find that such kinetic processes are effective only in supercritical shocks above a critical Mach number, $Ms{\ast}{\sim}2.3$. In addition, even in shocks with Ms > 2.3, energized electrons may not reach high energies to be injected to DSA, because the oblique EFI alone fails to generate long-wavelength waves. Our results should have implications for the origin and nature of radio relics.

• 대한화학회지
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• 제56권6호
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• pp.679-691
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• 2012

New series of metal complexes of Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and Pt(II) with 4-(p-chlorophenyl)-1-(pyridin-2-yl)thiosemicarbazide (HCPTS) have been synthesized and characterized by elemental analyses, magnetic moment, spectra (IR, UV-Vis, $^1H$ NMR, mass and ESR) and thermal studies. The IR data suggest different coordination modes for HCPTS which behaves as a monobasic bidentate with all metal ions except Cu(II) and Zn(II) which acts as a monobasic tridentate. Based on the electronic and magnetic studies, Co(II), Cu(II), Pd(II) and Pt(II) complexes have square - planner, Ni(II) has mixed stereochemistry (tetrahedral + square planar), while Zn(II) is tetrahedral. Molar conductance in DMF solution indicates the non-ionic nature of the complexes. The ESR spectra of solid copper(II) complex show $g_{\parallel}$ (2.2221) > $g_{\perp}$ (2.0899) > 2.0023 indicating square-planar structure and the presence of the unpaired electron in the $d_x2_{-y}2$ orbital with significant covalent bond character. The thermal stability and degradation kinetics of the ligand and its metal complexes were studied by TGA and DTA and the kinetic parameters were calculated using Coats-Redfern and Horowitz-Metzger methods. The complexes have more antibacterial activity against some bacteria than the free ligand. However, the ligand has high anticancer activities against HCT116 (human colon carcinoma cell line) and HEPG2 (human liver hepatocellular carcinoma cell line) compared with its complexes.