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Chung Tae-Wook,Lee Dong-Ick,Kim Dong-Soo,Jin Un-Ho,Park Chun,Kim Jong-Guk,Kim Min-Gon,Ha Sang-Do,Kim Keun-Sung,Lee Kyu-Ho,Kim Kwang-Yup,Chung Duck-Hwa,Kim Cheorl-Ho The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.3
Two pathways of ammonium assimilation and glutamate biosynthesis have been identified in microorganisms. One pathway involves the NADP-linked glutamate dehydrogenase, which catalyzes the amination of 2-oxoglutarate to form glutamate. An alternative pathway involves the combined activities of glutamine synthetase, which aminates glutamate to form glutamine, and glutamate synthase, which transfers the amide group of glutamine to 2-oxoglutarate to yield two molecules of glutamate. We have cloned the large subunit of the glutamate synthase (GOGAT) from Salmonella typhimurium by screening the expression of GOGAT and complementing the gene in E. coli GOGAT large subunit-deficient mutants. Three positive clones (named pUC19C12, pUC19C13 and pUC19C15) contained identical Sau3AI fragments, as determined by restriction mapping and Southern hybridization, and expressed GOGAT efficiently and constitutively using its own promoter in the heterologous host. The coding region expressed in Escherichia coli was about 170 kDa on SDS-PAGE. This gene spans 4,732 bases, contains an open reading frame of 4,458 nucleotides, and encodes a mature protein of 1,486 amino acid residues (Mr =166,208). The EMN-binding domain of GOGAT contains 12 glycine residues, and the 3Fe-4S cluster has 3 cysteine residues. The comparison of the translated amino acid sequence of the Salmonella GOGAT with sequences from other bacteria such as Escherichia coli, Salmonella enterica, Shigella flexneri, Yersinia pestis, Vibrio vulnificus and Pseudomonas aeruginosa shows sequence identity between 87 and 95%.
Effects of N-acetyl Cysteine as Precursor of GSH in RA-induced Neuronal Differentiation of P19 ESCs
Joon Yup Kim,Jiae Park,Yoo Hun Noh,Do Hee Kim,Ok Hyeon Kim,Yoon Hee Chung,Kyung Yong Kim,Seung Ho Han,Sung Su Kim,Won Bok Lee 중앙대학교 의과대학 의과학연구소 2013 中央醫大誌 Vol.38 No.2
N-acetyl cysteine (NAC), estradiol and melatonin are well-known as antioxidant, and these reagents have a strong influence on many cellular events. Therefore, we compared effects of NAC in Retinoic acid (RA)-induced embryonic body's (EB) formation and neuronal differentiation of P19 embryonic stem cells (P19 ESCs) with estradiol and melatonin. NAC dramatically increased EB formation and neuronal differentiation in terms of neuronal marker, MAP-2, and neuronal maturation. However, in additional treated groups with estradiol and melatonin, no differences were founded as contrasted with NAC treatment. Furthermore, in NAC-enhanced neuronal differentiation, intracellular glutathione (GSH) contents was only increased, and co-treatment with buthionine sulphoximine (BSO), a GSH-synthesis inhibitor, effectively reduced the EB formation and neuronal differentiation. These results demonstrated that NAC increase EB formation and neuronal differentiation by up-regulation of intracellular GSH contents. NAC-enhanced neuronal differentiation effects may be as donor of GSH, not as antioxidant.
Kim, Kwang-Woon,Kim, Sun-Hee,Lee, Eun-Yup,Kim, Nam-Deuk,Kang, Ho-Sung,Kim, Han-Do,Chung, Byung-Seon,Kang, Chi-Dug 부산대학교 유전공학연구소 2001 분자생물학 연구보 Vol.17 No.-
Two signaling pathways, the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK)-dependent pathway and the nuclear factor-κB (NF-κB)-dependent pathway, have been known to mediate megakaryocytic differentiation of K562 cells induced by phorbol 12-myristate 13-acetate (PMA). In this study, we examined whether 90-kDa ribosomal S6 kinase (RSK), known as a substrate of ERK/MAPK and a signal-inducible IκBα kinase, would link two pathways during the differentiation. RSK_1 was ctivated in a time- and dose-dependent manner during the PMA-induced differentiation. Overexpression of wild-type or dominant inhibitory mutant (D205N) of RSK_1 enhanced or suppressed PMA-stimulated NF-κB activation and megakaryocytic differentiation as shown by expression of the CD41 megakaryocytic marker, respectively. In addition, overexpression of the dominant inhibitory mutant (S32A/S36A) of IκBα inhibited PMA-stimulated and RSK1-enhanced megakaryocytic differentiation downstream of RSK1. PMA-stimulated activation of ERK/MAPK, RSK1, and NF-κB and the PMA-induced megakaryocytic differentiation were prevented by pretreatment with PD98059, a specific inhibitor of the mitogen-activated ERK kinase (MEK). Therefore, these results demonstrate that the sequential ERK/RSK1/NF-κB pathway mediates PMA-stimulated megakaryocytic differentiation of k562 cells.
Kim, Jung-Sun,Kim, Byung-Soo,Kim, Ji-Ha,Park, Choon-Sik,Chung, Il-Yup 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.7
Nanog is a key determinant that maintains self-renewal and pluripotency of embryonic stem cells and represses their differentiation to endoderm. In this study, we examined the regulation of Nanog expression by phosphoinositide-3-kinase (PI3K)/Akt pathway during retinoic acid (RA)-induced differentiation of F9 embryonic carcinoma cells. Nanog protein expression was transiently upregulated up to 6 h after RA treatment and then declined. In agreement, a murine Nanog promoter reporter assay revealed that promoter activity increased during early stage of differentiation, but decreased when F9 cells became fully differentiated. RA treatment of F9 cells also led to a transient and parallel increase in both Akt and glycogen synthase kinase 3${\beta}$ phosphorylations. Nanog expression was diminished in the early stage by LY294002, a PI3K inhibitor, but was not affected in the late stage despite considerable inhibition of Akt phosphorylation and endoderm marker expression by the inhibitor. These data suggest that RA-induced PI3K/Akt activation in the early stage of differentiation is required for Nanog expression, which becomes independent of PI3K/Akt signaling once the differentiation is established. Thus, Nanog expression appears to be differently regulated by the PI3K/Akt pathway depending on differentiation stage.
Kim Tae Jung,Lee Hak Seung,Kim Seong-Eun,Park Jinju,Kim Jun Yup,Lee Ji Yoon,Song Ji Eun,Hong Jin-Hyuk,Lee Joongyub,Chung Joong-Hwa,Kim Hyeon Chang,Shin Dong-Ho,Lee Hae-Young,Kim Bum Joon,Seo Woo-Keun 질병관리청 2024 Osong Public Health and Research Persptectives Vol.15 No.1
Objectives: Limited information is available concerning the epidemiology of stroke and acute myocardial infarction (AMI) in the Republic of Korea. This study aimed to develop a national surveillance system to monitor the incidence of stroke and AMI using national claims data.Methods: We developed and validated identification algorithms for stroke and AMI using claims data. This validation involved a 2-stage stratified sampling method with a review of medical records for sampled cases. The weighted positive predictive value (PPV) and negative predictive value (NPV) were calculated based on the sampling structure and the corresponding sampling rates. Incident cases and the incidence rates of stroke and AMI in the Republic of Korea were estimated by applying the algorithms and weighted PPV and NPV to the 2018 National Health Insurance Service claims data.Results: In total, 2,200 cases (1,086 stroke cases and 1,114 AMI cases) were sampled from the 2018 claims database. The sensitivity and specificity of the algorithms were 94.3% and 88.6% for stroke and 97.9% and 90.1% for AMI, respectively. The estimated number of cases, including recurrent events, was 150,837 for stroke and 40,529 for AMI in 2018. The age- and sex-standardized incidence rate for stroke and AMI was 180.2 and 46.1 cases per 100,000 person-years, respectively, in 2018.Conclusion: This study demonstrates the feasibility of developing a national surveillance system based on claims data and identification algorithms for stroke and AMI to monitor their incidence rates.
Kim, Hee-Jeong,Cho, Sung-Hwan,Park, Jong-Sook,Lee, Tae-Hyeong,Lee, Eun-Ju,Kim, Yong-Hoon,Uh, Soo-Taek,Chung, Il Yup,Kim, Mi-Kyeong,Choi, Inseon S,Park, Byung-Lae,Shin, Hyoung-Doo,Park, Choon-Sik Springer-Verlag 2012 Journal of human genetics Vol.57 No.4
<P>Aspirin-exacerbated respiratory diseases (AERD) are associated with the metabolism of arachidonic acid. FPR2 (formyl peptide receptor2) is a high-affinity ligand receptor for potent anti-inflammatory lipid metabolites: lipoxins. Thus, functional alterations of the FPR2 may contribute to AERD. We investigated the relationship between single-nucleotide polymorphisms (SNPs) in the FPR2 and AERD. Asthmatics were categorized into AERD <15% decreases in forced expiratory volume in one second (FEV(1)), and/or naso-ocular reactions after oral aspirin challenge (n=170) and aspirin-tolerant asthma (ATA, n=268). In all, 11 SNPs were genotyped. FPR2 protein expressions on CD14-positive monocytes in peripheral blood were measured using flow cytometric analysis. We performed RT-PCR of the FPR2 mRNA expressed by peripheral blood mononuclear cells. Logistic regression analysis showed that the minor allele frequency of FPR2 -4209T>G (rs1769490) in intron 2 was significantly lower in the AERD group (n=170) than in the ATA group (n=268) (P=0.006, P(corr)=0.04, recessive model). The decline of FEV(1) after aspirin challenge was significantly lower in the subjects with GG homozygotes of FPR2 -4209T>G than those with the other genotypes (P=0.0002). Asthmatic homozygotes for FPR2 -4209T>G minor allele exhibited significantly higher FPR2 protein expression in CD14-positive monocytes than did those with the common allele of FPR2 -4209T>G allele (P=0.01). There was no difference in the expression of the wild form and the exon 2 deleted variant form of FPR2 gene according to the genotypes of FPR2 -4209T>G. The minor allele at FPR2 -4209T>G may have a protective role against the development of AERD, via increase of FPR2 protein expression in inflammatory cells.</P>
Kim, Jae-Yup,Jang, Youn Jeong,Park, Jongwoo,Kim, Jeehye,Kang, Jin Soo,Chung, Dong Young,Sung, Yung-Eun,Lee, Changhee,Lee, Jae Sung,Ko, Min Jae Elsevier 2018 Applied Catalysis B Vol.227 No.-
<P><B>Abstract</B></P> <P>Among the various renewable sources of energy, solar energy conversion systems have been regarded as a promising way to satisfy the growing energy demand. For superior solar energy conversion performance, it is important to utilize efficient photosensitizers that have excellent light-harvesting capability. In this regard, quantum dots (QDs) are promising photosensitizer candidates owing to their high absorption coefficient, band gap tunability, and potential multiple exciton generation. Here, we report an effective and straightforward approach to improve the loadings of nanocomposite PbS/CdS QDs in a mesoporous electrode, for highly efficient solar energy conversion. By controlling the surface charge of TiO<SUB>2</SUB> during the successive ionic layer adsorption and reaction process, both the PbS and CdS QD loadings are distinctly increased, leading to a highly enhanced light-harvesting capability of the photoelectrodes. This enhancement is effectively applied not only for solar-to-electrical but also for solar-to-chemical energy conversion, resulting in a ∼33% increased conversion efficiency of the QD solar cells and an unprecedented photocurrent of 22.1 mA/cm<SUP>2</SUP> (at 0.6 V vs<I>.</I> RHE) for hydrogen production from photoelectrochemical water splitting. These results provide significant insight into the application of QD photosensitizers in solar energy conversion.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PbS/Mn-doped CdS QDs were loaded on a mesoporous electrode. </LI> <LI> The QD loadings were increased by controlling the electrode surface charge. </LI> <LI> Due to the enhanced QD loadings, the efficiency of QD solar cells was increased by ∼33%. </LI> <LI> When applied in PEC water splitting, a remarkable photocurrent density of 22.1 mA/cm<SUP>2</SUP> was obtained. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Interactive Direct Interhospital Transfer Network System for Acute Stroke in South Korea
Inyoung Chung,Hee-Joon Bae,Beom Joon Kim,Jun Yup Kim,Moon-Ku Han,Jinhwi Kim,Cheolkyu Jung,Jihoon Kang 대한신경과학회 2023 Journal of Clinical Neurology Vol.19 No.2
Background and Purpose Interhospital transfer is an essential practical component of regional stroke care systems. To establish an effective stroke transfer network in South Korea, an interactive transfer system was constructed, and its workflow metrics were observed. Methods In March 2019, a direct transfer system between primary stroke hospitals (PSHs) and comprehensive regional stroke centers (CSCs) was established to standardize the clinical pathway of imaging, recanalization therapy, transfer decisions, and exclusive transfer linkage systems in the two types of centers. In an active case, the time metrics from arrival at PSH (“door”) to imaging was measured, and intravenous thrombolysis (IVT) and endovascular treatment (EVT) were used to assess the differences in clinical situations. Results The direct transfer system was used by 27 patients. They stayed at the PSH for a median duration of 72 min (interquartile range [IQR], 38–114 min), with a median times of 15 and 58 min for imaging and subsequent processing, respectively. The door-to-needle median times of subjects treated with IVT at PSHs (n=5) and CSCs (n=2) were 21 min (IQR, 20.0–22.0 min) and 137.5 min (IQR, 125.3–149.8 min), respectively. EVT was performed on seven subjects (25.9%) at CSCs, which took a median duration of 175 min; 77 min at the PSH, 48 min for transportation, and 50 min at the CSC. Before EVT, bridging IVT at the PSH did not significantly affect the door-to-puncture time (127 min vs. 143.5 min, p=0.86). Conclusions The direct and interactive transfer system is feasible in real-world practice in South Korea and presents merits in reducing the treatment delay by sharing information during transfer.