• Journal of Plant Biotechnology
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• 제2권2호
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• pp.79-82
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• 2000

We have isolated a cDNA encoding a calcium-dependent protein kinase (CDPK) in Nicotiana tabacum, which was designated NtCDPK1. Accumulation of the NtCDPK1 mRNA was stimulated by various stimuli, including phytohormones, CaCl$_2$ wounding, fungal elicitors, chitin and methyl jasmonate. The NtCDPK1 gene encodes a functional Ser/Thr protein kinase of which phosphorylation activity is strongly induced by calcium. By analyzing expression of the NtCDPK1-GFP fusion protein and by immunoblotting with antibody which reacts with NtCDPK1, we found that NtCDPK1 is localized in membrane and nucleus in plant cells. Silencing expression of the NtCDPK1 transgene resulted in marked decrease of lateral root development in the transgenic tobacco plants. Yeast two hybrid screening using NtCDPK1 as a bait identified a tobacco homologue of proteasome regulatory subunit 21D7, designated Nt21D7. The 21D7 mRNA has been shown to be predominantly expressed in proliferating tissues in the cell cycledependent manner in carrot. The recombinant NtCDPK1 protein associated with Nt21D7 in vitro, and could phosphorylate the Nt21D7 protein in vitro in the presence of calcium, suggesting that Nt21D7 protein is a natural substrate of NtCDPK1 in tobacco. These results suggest that NtCDPK1 may regulate tell proliferation processes, such as lateral root formation, by regulating specificity and/or activity of proteasome-mediated protein degradation pathway.

• 한국환경성돌연변이발암원학회지
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• 제22권4호
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• pp.259-265
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• 2002

Phthalate analogues are a plasticizer and solvent used in industry. Phthalates were reported to be a potential carcinogen classified in the category of suspected endocrine disruptors. Most common human exposure to these compounds may occur with contaminated food. They may migrate into food from plastic wrap or may enter food from general environmental contamination. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of phthalates that possibly threaten the public health. Concern about their use has been mounting. To screen and elucidate the endocrine disrupting activity and their mechanism of phthalate analogues, first of all, E-screen assay was performed in MCF7 human breast cancer cells with seven phthalate analogues. In this cell proliferation assay, only dibutyl phthalate (DBP) showed weak estrogenic activity. Also the yeast-based transcription assay to assess the interactions of DBP with the estrogen, androgen, and progesterone receptors was conducted. DBP in the concentration ranges from 10$^{-16}$ to 10$^{-11}$ M was active in the estrogen transcriptional assay, but it did not show the effect on $\beta$-galactosidase activity in the progesterone and androgen transcriptional assays. These data indicate that DBP shows estrogenic potential and can be classified as weak and/or suspected endocrine disrupting chemicals.

• 미생물학회지
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• 제52권1호
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• pp.116-119
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• 2016

텔로미어를 안정적으로 유지하는 것은 세포의 증식과 생존에 필수적이다. 비록 텔로미어 유지에는 telomerase가 가장 중요한 수단이지만 재조합도 텔로미어 유지를 위한 또 다른 중요한 과정으로 작용한다. 본 연구에서는 효모의 텔로미어 내부에 존재하는 $TG_{1-3}$ 반복서열을 이용하여 텔로미어 재조합을 관찰할 수 있는 유전학적 방법을 개발하였다. 관찰된 재조합 빈도는 내부 $TG_{1-3}$ 반복서열의 존재 여부에 영향을 받았으며, 생성된 $FOA^rCan^r$ 콜로니로부터 추출한 유전체 DNA를 사용하여 URA3와 CAN1 marker 근처 부위를 PCR 증폭한 결과, 각 콜로니들은 marker를 포함한 염색체 말단 부위가 결손 된 것으로 나타났다. 뿐만 아니라, 더 긴 내부 $TG_{1-3}$ 반복서열을 사용하였을 때 재조합 빈도는 더 증가하였다. 이러한 결과는 $FOA^rCan^r$ 콜로니 형성이 내부와 말단의 $TG_{1-3}$ 반복서열 사이의 재조합에 기인한다는 것을 의미한다.

• 한국자원식물학회지
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• 제23권5호
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• pp.415-422
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• 2010

홍삼은 인삼을 증숙하는 과정에서 생겨나는 화학적으로 변화된 생리활성물질들에 의해 인삼과 차별화된 효과를 보여준다. 또한 홍삼은 장내미생물의 생물학적 전환에 의해 변화되어 생체내 약리활성을 보이는데, 이는 개인의 장내 미생물의 분포 차이에 의해 약리작용의 차이를 보일 수 있다. 최근 이 같은 차이를 극복하기 위해 인위적으로 장내미생물에 의해 사전 발효시킨 발효홍삼은 홍삼과 다른 성분량의 차이를 보임으로써 독특한 약리작용을 보인다고 알려져 있다. 이에 본 연구는 홍삼과 발효홍삼의 추출물이 알러지 및 염증반응에 끼치는 영향에 대해 알아보기 위해 비만세포의 탈과립 과정에서 분비되는 $\beta$-hexosaminidase 분비량 비교, 염증매개 세포부착물질인 ICAM-1 발현비교, 생쥐림프구의 증식능, 각질형성세포 증식능을 상호 비교하였다. 실험결과 홍삼은 1, $10\;{\mu}g/ml$에서 $\beta$-hexosaminidase 분비량 억제 및 ICAM-1 발현 억제 조절 효과를 나타내었으며, 발효 홍삼은 모든 농도에서 유의적인 억제 효과를 나타내었다. 그러므로 홍삼과 발효홍삼에서는 모두 항알러지 및 항염증 효과가 있다고 사료된다. 그러나 LPS에 의한 B세포의 증식능에서 홍삼 $1\;{\mu}g/ml$은 증가효과를 발효홍삼에서는 $100\;{\mu}g/ml$에서 억제효과를 나타내었고, ConA에 의한 T세포의 증식능에서는 홍삼 $100\;{\mu}g/ml$에서 증가효과를 발효홍삼 $100\;{\mu}g/ml$에서는 억제효과를 나타냄으로써 림프구 증식능에 관한 실험에서는 두 추출물간에 상반된 효과를 나타내었다. HaCaT세포를 이용한 각질형성세포 증식능에서는 발효홍삼 1, $10\;{\mu}g/ml$에서만 효과를 나타내었다. 이러한 결과를 종합해 볼 때, 홍삼과 발효홍삼에 존재하는 성분량의 변화에 따라 그 효능에서 차이를 나타내고 있는 것으로 사료되며, 홍삼 및 발효홍삼의 고농도 $100\;{\mu}g/ml$에서는 저농도와는 다른 효과를 보이는 경향을 나타내고 있으므로 홍삼 및 발효홍삼의 사용에 있어 적절한 적응증과 주성분의 검증 및 유효 농도에 대한 연구가 더욱 필요하다고 판단된다.

• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1098-1105
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• 2017

Vesicular stomatitis virus G glycoprotein (VSV-G) has been widely used for pseudotyping retroviral, lentiviral, and artificial viral vectors. The objective of this study was to establish a potential approach for large-scale production of VSV-G. To this end, VSV-G was cloned with an N-terminal His-tag into Pichia pastoris expression vector pPIC3.5K. Three clones ($Mut^s$) containing the VSV-G expression cassette were identified by PCR. All clones proliferated normally in expansion medium, whereas the proliferation was reduced significantly under induction conditions. VSV-G protein was detected in cell lysates by western blot analysis, and the highest expression level was observed at 96 h post induction. VSV-G could also be obtained from the condition medium of yeast protoplasts. Furthermore, VSV-G could be incorporated into Ad293 cells and was able to induce cell fusion, leading to the transfer of cytoplasmic protein. Finally, VSV-G-mediated DNA transfection was assayed by flow cytometry and luciferase measurement. Incubation of VSV-G lysate with the pGL3-control DNA complex increased the luciferase activity in Ad293 and HeLa cells by about 3-fold. Likewise, incubation of VSV-G lysate with the pCMV-DsRed DNA complex improved the transfection efficiency into Ad293 by 10% and into HeLa cells by about 1-fold. In conclusion, these results demonstrate that VSV-G could be produced from P. pastoris with biofunctionalities, demonstrating that large-scale production of the viral glycoprotein is feasible.

• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.591-597
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• 2003

Human urokinase kringle domain, sharing homology with angiostatin kringles, has been shown to be an inhibitor of angiogenesis, which can be used for the treatment of cancer, rheumatoid arthritis, psoriasis, and retinopathy. Here, the expression of the kringle domain of urokinase (UK1) as a secreted protein in high levels is reported. UK1 was expressed in the methylotrophic yeast Pichia pastoris GS115 by fusion of the cDNA spanning from Ser47 to Lys135 to the secretion signal sequence of ${\alpha}-factor$ prepro-peptide. In a flask culture, the secreted UK1 reached about 1 g/l level after 120h of methanol induction and was purified to homogeneity by ion-exchange chromatography. Amino-terminal sequencing of the purified UK1 revealed that it was cleaved at the Ste13 signal cleavage site. The molecular mass of UK1 was determined to be 10,297.01 Da. It was also confirmed that the purified UK1 inhibited endothelial cell proliferation stimulated by basic fibroblast growth factor, vascular endothelial growth factor, or epidermal growth factor, in a dose-dependent manner. These results suggest that a P. pastoris sytem can be employed to obtain large amounts of soluble and active UK1.

• Molecules and Cells
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• 제40권11호
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• pp.805-813
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• 2017

The role of phospholipase D (PLD) in cancer development and management has been a major area of interest for researchers. The purpose of this mini-review is to explore PLD and its distinct role during chemotherapy including anti-apoptotic function. PLD is an enzyme that belongs to the phospholipase super family and is found in a broad range of organisms such as viruses, yeast, bacteria, animals, and plants. The function and activity of PLD are widely dependent on and regulated by neurotransmitters, hormones, small monomeric GTPases, and lipids. A growing body of research has shown that PLD activity is significantly increased in cancer tissues and cells, indicating that it plays a critical role in signal transduction, cell proliferation, and anti-apoptotic processes. In addition, recent studies show that PLD is a downstream transcriptional target of proteins that contribute to inflammation and carcinogenesis such as Sp1, $NF{\kappa}B$, TCF4, ATF-2, NFATc2, and EWS-Fli. Thus, compounds that inhibit expression or activity of PLD in cells can be potentially useful in reducing inflammation and sensitizing resistant cancers during chemotherapy.

• Molecules and Cells
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• 제22권1호
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• pp.113-118
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• 2006

Thioredoxin reductase (TrxR), a component of the redox control system involving thioredoxin (Trx), is implicated in defense against oxidative stress, control of cell growth and proliferation, and regulation of apoptosis. In the present study a stable transfectant was made by introducing the vector pcDNA3.0 harboring the fission yeast TrxR gene into COS-7 African green monkey kidney fibroblast cells. The exogenous TrxR gene led to an increase in TrxR activity of up to 3.2-fold but did not affect glutathione (GSH) content, or glutaredoxin and caspase-3 activities. Levels of reactive oxygen species (ROS), but not those of nitric oxide (NO), were reduced. Conversely, 1-chloro-2,4-dinitrobezene (CDNB), an irreversible inhibitor of mammalian TrxR, enhanced ROS levels in the COS-7 cells. After treatment with hydrogen peroxide, the level of intracellular ROS was lower in the transfectants than in the vector control cells. These results confirm that TrxR is a crucial determinant of the level of cellular ROS during oxidative stress as well as in the normal state.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1863-1868
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• 2004

Kringle 5 (K5), located outside of angiostain (K1-4) in human plasminogen, displays more potent antiangiogenic activity on endothelial cell proliferation than angiostatin itself. Using a yeast two-hybrid system in vivo, we have recently identified Rgl2 (guanine nucleotide dissociation stimulator (RalGDS)-like factor 2) as a binding protein of human K5. In order to confirm in vitro protein interaction between K5 and Rgl2, we developed bacterial recombinant expression systems for them. K5 and Rgl2 proteins were expressed in high yields and purified into pure forms with His tags and GST fusion, respectively. GST-pull down experiments clearly demonstrated that K5 interacts specifically with Rgl2 in vitro. These results indicate that Rgl2 functions as a receptor protein for K5 in vitro as well as in vivo, leading to anti-angiogenesis through regulating Ras signaling pathways.

• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.367-374
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• 2000

The composition of dissolved gases and nutrients in a liquid medium were determined for establishment of the optimum conditions for in vitro culture of Helicobacter pylori. A microaerobic condition facored by the organism was prepared by adjusting the partial pressure of the gas, agitation speed, and viscosity of the medium. The gaseous concentrations were controlled by utilizing CampyPak Plus that reduced oxygen while augmenting carbon dioxide. Agitation of the broth facilitated the oxygen transfer to the cells, yet inhibited the growth at high rates. An increase of viscosity in the medium repressed the culture although this variable was relatively insignificant. The chemical constituents of the liquid broth were examined to establish an economic model for H. pylori cultivation. The microbe required a neutral pH for optimum growth, and yet was also able to proliferate in an acidic condition, presumably by releasing the acidity-modulating enzyme, urease. Cyclodextrin and casamino acid were investigated as growth enhancers in place of serum, while yeast extract unexpectedly inhibited the cells. A low concentration of glucose, the unique carbon source for the organism, increased the cell density, yet high concentrations resulted in an adverse effect. Under optimally dissolved gas conditions, the cell concentration in brucella broth supplemented with serum substitutes and glucose reached $1.6{\times}10^8$ viable cells/ml which was approximately 50% higher than that obtained in the liquid medium added with only cyclodextrin or serum.