• Journal of Plant Biotechnology
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• 제7권1호
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• pp.27-35
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• 2005

Eighty-five different cultivars of Brassica rapa, B. juncea, B. nap us, B. carinata, B. oleracea and hexaploid Brassica collected from Bangladesh, Japan, China and Denmark were analyzed by SDS-PAGE for seed and leaf protein variations, using esterase, acid phosphatase and peroxidase isozyme analysis. Ten polymorphic bands were identified from seed protein however no identifiable polymorphic band was found in the leaf protein. Polymorphic markers clearly distinguished the different Brassica species as well as yellow sarson (YS) and brown seeded (BS) cultivars of B. rapa. The $F_1$ cross between YS and brown seeded cultivars showed the existance of all poly-morphic bands of the respective parents. The Bangla-deshi and Japanese cultivars of B. rapa differed in the amount of seed protein. In the case of isozyme analysis, esterase showed the highest number of polymorphic bands (13) followed by acid phosphatase (9) and peroxidase (5). These polymorphic markers were very effec-tive for classification of all the species studied in this experiment. In parentage tests using isozymes, the hybridity of intra-and-interspecific crosses of almost all the seedlings could be identified from their respective cross combinations. Esterase polymorphism showed a clear differentiation between YS and BS types of B. rapa. In addition, two esterase polymorphic markers were iden ified to differentiate some cultivars of B. juncea. Segregation patterns in these two esterase bands showed a simple Mendelian monohybrid ratio of 3:1 in $F_2$, 1:1 in test cross and 1:0 in back cross progenies. No polymorphic band was identified to distinguish different cultivars of the same species by acid phosphatase or peroxidase. Polymerase Chain Reaction (PCR) was carried out with seed coat color specific marker of B. juncea. The yellow seeded cultivars produced a strong band at 0.5 kb and weak band 1.2 kb. In the addition of these two specific bands, Japanese yellow-seeded cultivars expressed two more weak bands at 1.0 kb and 1.1 kb. Where the brown seeded cultivars generated a single strong band at 1.1 kb. In segregating population, the yellow seed coat color marker segregated at a ratio 15 (brown) : 1 (yellow), indicating the digenic inheritance pattern of the trait.

• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.389-396
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• 2009

Objective : Triptolide (TP) has been reported to suppress the expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1), of which main function is to inactivate the extracellular signal-regulated kinase-1/2 (ERK-1/2), the p38 MAPK and the c-Jun N-terminal kinase-1/2 (JNK-1/2), and to exert antiproliferative and pro-apoptotic activities. However, the mechanisms underlying antiproliferative and pro-apoptotic activities of TP are not fully understood. The purpose of this study was to examine whether the down-regulation of MKP-1 expression by TP would account for antiproliferative activity of TP in immortalized HT22 hippocampal cells. Methods : MKP-1 expression and MAPK phosphorylation were analyzed by Western blot. Cell proliferation was assessed by $^3H$-thymidine incorporation. Small interfering RNA (siRNA) against MKP-1, vanadate (a phosphatase inhibitor), U0126 (a specific inhibitor for ERK-1/2), SB203580 (a specific inhibitor for p38 MAPK), and SP600125 (a specific inhibitor for JNK-1/2) were employed to evaluate a possible mechanism of antiproliferative action of TP. Results : At its non-cytotoxic dose, TP suppressed MKP-1 expression, reduced cell growth, and induced persistent ERK-1/2 activation. Similar growth inhibition and ERK-1/2 activation were observed when MKP-1 expression was blocked by MKP-1 siRNA and its activity was inhibited by vanadate. The antiproliferative effects of TP, MKP-1 siRNA, and vanadate were significantly abolished by U0126, but not by SB203580 or SP600125. Conclusion : Our findings suggest that TP inhibits the growth of immortalized HT22 hippocampal cells via persistent ERK-1/2 activation by suppressing MKP-1 expression. Additionally, this study provides evidence supporting that MKP-1 may play an important role in regulation of neuronal cell growth.

• BMB Reports
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• 제46권6호
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• pp.289-294
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• 2013

To maintain cellular homeostasis against the demands of the extracellular environment, a precise regulation of kinases and phosphatases is essential. In cell cycle regulation mechanisms, activation of the cyclin-dependent kinase (CDK1) and cyclin B complex (CDK1:cyclin B) causes a remarkable change in protein phosphorylation. Activation of CDK1:cyclin B is regulated by two auto-amplification loops-CDK1:cyclin B activates Cdc25, its own activating phosphatase, and inhibits Wee1, its own inhibiting kinase. Recent biological evidence has revealed that the inhibition of its counteracting phosphatase activity also occurs, and it is parallel to CDK1:cyclin B activation during mitosis. Phosphatase regulation of mitotic kinases and their substrates is essential to ensure that the progression of the cell cycle is ordered. Outlining how the mutual control of kinases and phosphatases governs the localization and timing of cell division will give us a new understanding about cell cycle regulation.

• 대한본초학회지
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• 제37권1호
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• pp.51-59
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• 2022

Objectives : The process through which mesenchymal cells condense and differentiate into chondrocytes to form new bone is known as endochondral bone formation. Chondrogenic differentiation and hypertrophy are essential steps in bone formation and are influenced by various factors. The stem bark and root bark of Eleutherococcus sessiliflorus (ES) have been widely used to treat growth retardation and arthritis in traditional Korean Medicine. In this study, we aimed to investigate the possible role of the stem bark of ES in the stimulation of chondrogenic differentiation in clonal murine chondrogenic ATDC5 cells. Methods : In ATDC5 cells treated with ES extract, cell viability and extracellular matrix production were determined using CCK-8 assay and Alcian blue staining, respectively, and alkaline phosphatase activity was measured. We also examined mRNA and protein expression levels of genes related to chondrogenic expression in ATDC5 cells using reverse transcription-polymerase chain reaction and western blot analyses. Results : ES extract increased the accumulation of Alcian blue-stained cartilage nodules and alkaline phosphatase activity in ATDC5 cells. It increased the mRNA expressions of chondrogenic markers including bone sialoprotein (BSP), cartilage collagens, Runt-related transcription factor-2 (RUNX-2), osteocalcin (OCN), β-catenin, and bone morphogenetic protein-2 (BMP-2), as well as the protein expressions of β-catenin, RUNX-2, BMP-2, and alkaline phosphatase (ALP). Conclusion : Taken together, these results suggest that ES extract exhibits a chondromodulating activity and therefore may be a possible agent for the treatment of bone growth disorders.

• 공업화학
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• 제8권4호
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• pp.610-616
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• 1997

낙동강에서 채취한 남조류 Microcystis로부터 간독성물질이자 protein phosphatase 1과 2A의 강력한 억제제인 microcystin-LR과 microcystin-RR을 분리하였다. 이들 물질의 독성과 구조와의 관계들을 알아보기 위하여 몇가지 유도체들을 합성하여 독성실험을 하였다. Glu와 MeAsp의 카르복실기를 에스테르화할 경우 독성을 잃어버리는 것을 알 수 있었다. 반면에 Mdha 잔기의 이중결합을 $NaBH_4$로 환원하여 Ala잔기로 전환한 경우에는 독성을 그대로 유지하였고 또한 microcystin-LR의 Arg잔기의 guanidyl기를 dimethylpyrimidyl기로 변환한 경우에도 독성에는 크게 영향을 주지 않는 것을 알 수 있었다. 따라서 2개의 카르복실기는 microcystin이 독성을 나타내는데 아주 중요한 역할을 하는 반면에, Mdha 및 Arg잔기의 존재는 큰 역할을 하지 않는 것으로 여겨진다.

• 대한화장품학회지
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• 제34권2호
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• pp.109-115
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• 2008

기질 화합물로써 $3{\beta}$-hydroxy-12-oleanen-28-oic acid 유도체들의 치환기($R_1{\sim}R_4$)가 변화함에 따른 protein tyrosine phosphatase(PTP)-1B의 저해활성에 관한 비교 분자장 분석(CoMFA) 모델을 유도하고 정량적으로 검토하였다. 최적의 CoMFA F1 모델은 가장 높은 예측성과 상관성($r^2_{cv.}=0.654$ 및 $r^2_{ncv.}=0.995$)을 나타내었다. 저해활성에 관한 CoMFA장 기여비율(%)의 순서는 입체장(53.0%), 정전기장(36.2%) 및 소수성장(10.8%) 이었다. 등고도 분석 결과로부터 저해활성은 기질 분자 내 $R_4$-치환기에 의존적이었으며 특히 melanin 저해활성이 높은 새로운 화합물(P1 및 P2)이 예측되었다.

• 동의생리병리학회지
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• 제22권6호
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• pp.1532-1536
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• 2008

Quercetin which isolated form the roots of Houttuynia cordata. was determined on the basis of IR, ID and 2D NMR specta by direct comparison with authentic compounds. Protein tyrosine phophatase 1B (PTP1B) is thought to be a negative regulator in insulin signal-transduction pathway. Insulin-resistance by the activation of PTP1B is a hallmark of both type 2 diabetes and obesity. Thus, the compound inhibiting PTP1B can improve insulin resistance and can be effective in treating type 2 diabetes and obesity. Quercetin which measured the inhibitory activity against PTP1B was 92.1% inhibition in the 30 ${\mu}g$/mL, 83.4% inhibition in the 6 ${\mu}g$/mL and 76.5% inhibition in the 3 ${\mu}g$/mL. These results suggest that quercetin retains a potential PTP1B activity.

• BMB Reports
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• 제49권7호
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• pp.370-375
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• 2016

Ras oncoproteins are small molecular weight GTPases known for their involvement in oncogenesis, which operate in a complex signaling network with multiple effectors. Approximately 25% of human tumors possess mutations in a member of this family. The Raf1/MEK/Erk1/2 pathway is one of the most intensively studied signaling mechanisms. Different levels of regulation account for the inactivation of MAP kinases by MAPK phosphatases in a cell type- and stimuli-dependent manner. In the present study, using three inducible Ras-expressing NIH/3T3 cell lines, we demonstrated that MKP3 upregulation requires the activation of the Erk1/2 pathway, which correlates with the shutdown of this pathway. We also demonstrated, by applying pharmacological inhibitors and effector mutants of Ras, that induction of MKP3 at the protein level is positively regulated by the oncogenic Ras/Raf/MEK/Erk1/2 signaling pathway.

• Journal of Microbiology
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• 제37권1호
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• pp.21-26
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• 1999

Two novel calcium-binding proteins, named CAB-I and CAB-II, have been isolated from Streptomyces coelicolor. Purification of the calcium-binding proteins involved heat treatment, fractionation with ammonium sulfate, acid treatment, anion exchange and hydrophobic interaction column chromatography, FPLC gel filtration, and preparative isoelectric focusing. A chelex competitive assay and 45Ca autoradiography verified the calcium-binding ability of the proteins. The major band CAB-II has an apparent molecular weight of 26,000 determined by SDS-polyacrylamide gel electrophoresis and 340,000 determined by gel filtration. The isoelectric point of this molecule showed the acidic nature of the molecule. N-terminal amino acid sequence analysis shows homology to rat Ca2+/calmodulin-dependent protein kinase-II (CAB-II) and yeast phosphoprotein phosphatase (CAB-I).

• BMB Reports
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• 제46권5호
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• pp.237-243
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• 2013

Heart failure is one of the leading causes of sudden death in developed countries. While current therapies are mostly aimed at mitigating associated symptoms, novel therapies targeting the subcellular mechanisms underlying heart failure are emerging. Failing hearts are characterized by reduced contractile properties caused by impaired $Ca^{2+}$ cycling between the sarcoplasm and sarcoplasmic reticulum (SR). Sarcoplasmic/endoplasmic reticulum $Ca^{2+}$ ATPase 2a (SERCA2a) mediates $Ca^{2+}$ reuptake into the SR in cardiomyocytes. Of note, the expression level and/or activity of SERCA2a, translating to the quantity of SR $Ca^{2+}$ uptake, are significantly reduced in failing hearts. Normalization of the SERCA2a expression level by gene delivery has been shown to restore hampered cardiac functions and ameliorate associated symptoms in pre-clinical as well as clinical studies. SERCA2a activity can be regulated at multiple levels of a signaling cascade comprised of phospholamban, protein phosphatase 1, inhibitor-1, and $PKC{\alpha}$. SERCA2 activity is also regulated by post-translational modifications including SUMOylation and acetylation. In this review, we will highlight the molecular mechanisms underlying the regulation of SERCA2a activity and the potential therapeutic modalities for the treatment of heart failure.