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447 result(s) for "Lee, Chang-Kyu"
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Molecular characterization of human respiratory syncytial virus in Seoul, South Korea, during 10 consecutive years, 2010–2019
Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections and hospitalization in infants and young children. Here, we analyzed the genetic diversity of RSV using partial G gene sequences in 84 RSV-A and 78 RSV- B positive samples collected in Seoul, South Korea, for 10 consecutive years, from 2010 to 2019. Our phylogenetic analysis revealed that RSV-A strains were classified into either the ON1 (80.9%) or NA1 (19.0%) genotypes. On the other hand, RSV-B strains demonstrated diversified clusters within the BA genotype. Notably, some sequences designated as BA-SE, BA-SE1, and BA-DIS did not cluster with previously identified BA genotypes in the phylogenetic trees. Despite this, they did not meet the criteria for the assignment of a new genotype based on recent classification methods. Selection pressure analysis identified three positive selection sites (amino acid positions 273, 274, and 298) in RSV-A, and one possible positive selection site (amino acid position 296) in RSV-B, respectively. The mean evolutionary rates of Korean RSV-A from 1999 to 2019 and RSV-B strains from 1991 and 2019 were estimated at 3.51 × 10 −3 nucleotides (nt) substitutions/site/year and 3.32 × 10 −3 nt substitutions/site/year, respectively. The population dynamics in the Bayesian skyline plot revealed fluctuations corresponding to the emergence of dominant strains, including a switch of the dominant genotype from NA1 to ON1. Our study on time-scaled cumulative evolutionary analysis contributes to a better understanding of RSV epidemiology at the local level in South Korea.
Estimating VS30 at South Korean Seismic Observatory Stations Through Horizontal and Vertical Ground Motions
This investigation attempts to estimate time-averaged shear wave velocity in the upper 30 m of surficial material, VS30, from the horizontal-to-vertical spectral ratios, HVSRs, of seismic observatory stations in the South Korean region. From 2016 to 2023, a collection of 783 three-component ground motions were obtained from 19 stations operated by the Korea Institute of Geoscience and Mineral Resources. HVSRs were extracted from 5% damped acceleration and velocity RotD50 response spectra at each site. Peak HVSR frequencies and amplitudes were extracted and regressed to field-measured VS30s at available sites. An evaluation of different frequency and amplitude conditions was made to ascertain any effects on the regression. Findings included confirmation on minimum frequency and having amplitude conditions were unnecessary. Additionally, another peak frequency to VS30 relationship derived from Central and Eastern North America captured most of the behavior found in the Korean dataset.
Evaluation of Toxicity and Efficacy of Inotodiol as an Anti-Inflammatory Agent Using Animal Model
Chaga mushroom (Inonotus obliquus) comprises polyphenolic compounds, triterpenoids, polysaccharides, and sterols. Among the triterpenoid components, inotodiol has been broadly examined because of its various biological activities. The purpose of this study is to examine inotodiol from a safety point of view and to present the potential possibilities of inotodiol for medical usage. From chaga mushroom extract, crude inotodiol (INO20) and pure inotodiol (INO95) were produced. Mice were treated with either INO20 or INO95 once daily using oral administration for repeated dose toxicity evaluation. Serum biochemistry parameters were analyzed, and the level of pro-inflammatory cytokines in the serum was quantified. In parallel, the effect of inotodiol on food allergic symptoms was investigated. Repeated administration of inotodiol did not show any mortality or abnormalities in organs. In food allergy studies, the symptoms of diarrhea were ameliorated by administration with INO95 and INO20. Furthermore, the level of MCPT-1 decreased by treatment with inotodiol. In this study, we demonstrated for the first time that inotodiol does not cause any detrimental effect by showing anti-allergic activities in vivo by inhibiting mast cell function. Our data highlight the potential to use inotodiol as an immune modulator for diseases related to inflammation.
Comparative Transcriptome Analysis of Adipose Tissues Reveals that ECM-Receptor Interaction Is Involved in the Depot-Specific Adipogenesis in Cattle
Adipocytes mainly function as energy storage and endocrine cells. Adipose tissues showed the biological and genetic difference based on their depots. The difference of adipocytes between depots might be influenced by the inherent genetic programing for adipogenesis. We used RNA-seq technique to investigate the transcriptomes in 3 adipose tissues of omental (O), subcutaneous (S) and intramuscular (I) fats in cattle. Sequence reads were obtained from Illumina HiSeq2000 and mapped to the bovine genome using Tophat2. Differentially expressed genes (DEG) between adipose tissues were detected by EdgeR. We identified 5797, 2156, and 5455 DEGs in the comparison between OI, OS, and IS respectively and also found 5657 DEGs in the comparison between the intramuscular and the combined omental and subcutaneous fats (C) (FDR<0.01). Depot specifically up- and down- regulated DEGs were 853 in S, 48 in I, and 979 in O. The numbers of DEGs and functional annotation studies suggested that I had the different genetic profile compared to other two adipose tissues. In I, DEGs involved in the developmental process (eg. EGR2, FAS, and KLF7) were up-regulated and those in the immune system process were down-regulated. Many DEGs from the adipose tissues were enriched in the various GO terms of developmental process and KEGG pathway analysis showed that the ECM-receptor interaction was one of commonly enriched pathways in all of the 3 adipose tissues and also functioned as a sub-pathway of other enriched pathways. However, genes involved in the ECM-receptor interaction were differentially regulated depending on the depots. Collagens, main ECM constituents, were significantly up-regulated in S and integrins, transmembrane receptors, were up-regulated in I. Different laminins were up-regulated in the different depots. This comparative transcriptome analysis of three adipose tissues suggested that the interactions between ECM components and transmembrane receptors of fat cells depend on the depot specific adipogenesis.
SOX2 plays a crucial role in cell proliferation and lineage segregation during porcine pre‐implantation embryo development
Objectives Gene regulation in early embryos has been widely studied for a long time because lineage segregation gives rise to the formation of a pluripotent cell population, known as the inner cell mass (ICM), during pre‐implantation embryo development. The extraordinarily longer pre‐implantation embryo development in pigs leads to the distinct features of the pluripotency network compared with mice and humans. For these reasons, a comparative study using pre‐implantation pig embryos would provide new insights into the mammalian pluripotency network and help to understand differences in the roles and networks of genes in pre‐implantation embryos between species. Materials and methods To analyse the functions of SOX2 in lineage segregation and cell proliferation, loss‐ and gain‐of‐function studies were conducted in pig embryos using an overexpression vector and the CRISPR/Cas9 system. Then, we analysed the morphological features and examined the effect on the expression of downstream genes through immunocytochemistry and quantitative real‐time PCR. Results Our results showed that among the core pluripotent factors, only SOX2 was specifically expressed in the ICM. In SOX2‐disrupted blastocysts, the expression of the ICM‐related genes, but not OCT4, was suppressed, and the total cell number was also decreased. Likewise, according to real‐time PCR analysis, pluripotency‐related genes, excluding OCT4, and proliferation‐related genes were decreased in SOX2‐targeted blastocysts. In SOX2‐overexpressing embryos, the total blastocyst cell number was greatly increased but the ICM/TE ratio decreased. Conclusions Taken together, our results demonstrated that SOX2 is essential for ICM formation and cell proliferation in porcine early‐stage embryogenesis. We analysed the phenotypes of SOX2 knockout and SOX2‐overexpressing pre‐implantation porcine embryos to understand the function of SOX2, one of the core transcription factors. In SOX2‐targeted embryos, total cell number decreased, and expression of pluripotent‐related genes and proliferation‐related genes decreased. Loss‐ and gain‐of‐function analysis revealed that SOX2 regulates total cell number and expression of pluripotent‐related genes and proliferation‐related genes. These results indicate that SOX2 plays important role in cell proliferation and ICM formation in porcine pre‐implantation embryos.
Changes in OCT4 expression play a crucial role in the lineage specification and proliferation of preimplantation porcine blastocysts
Objectives Curiosity about the role of OCT4, a core transcription factor that maintains inner cell mass (ICM) formation during preimplantation embryogenesis and the pluripotent state in embryonic development, has long been an issue. OCT4 has a species‐specific expression pattern in mammalian preimplantation embryogenesis and is known to play an essential role in ICM formation. However, there is a need to study new roles for OCT4‐related pluripotency networks and second‐cell fate decisions. Materials and Methods To determine the functions of OCT4 in lineage specification and embryo proliferation, loss‐ and gain‐of–function studies were performed on porcine parthenotes using microinjection. Then, we performed immunocytochemistry and quantitative real‐time polymerase chain reaction (PCR) to examine the association of OCT4 with other lineage markers and its effect on downstream genes. Results In OCT4‐targeted late blastocysts, SOX2, NANOG, and SOX17 positive cells were decreased, and the total cell number of blastocysts was also decreased. According to real‐time PCR analysis, NANOG, SOX17, and CDK4 were decreased in OCT4‐targeted blastocysts, but trophoblast‐related genes were increased. In OCT4‐overexpressing blastocysts, SOX2 and NANOG positive cells increased, while SOX17 positive cells decreased, and while total cell number of blastocysts increased. As a result of real‐time PCR analysis, the expression of SOX2, NANOG, and CDK4 was increased, but the expression of SOX17 was decreased. Conclusion Taken together, our results demonstrated that OCT4 leads pluripotency in porcine blastocysts and also plays an important role in ICM formation, secondary cell fate decision, and cell proliferation. We analyzed the phenotypes of OCT4 knockout and OCT4 overexpressing preimplantation porcine embryos to understand the function of OCT4, one of the core transcription factors. In the OCT4 targeted embryos, intact inner cell mass (ICM) was not formed, and the expression of pluripotency‐related genes and proliferation‐related genes was decreased. In OCT4 overexpression embryos, the expression of the primitive endoderm marker SOX17 was decreased and the expression of epiblast marker genes increased. These results suggest that OCT4 is involved in both cell fate decisions in porcine preimplantation embryos and also affects cell proliferation.
Protective Effects of Lanostane Triterpenoids from Chaga Mushroom in Human Keratinocytes, HaCaT Cells, against Inflammatory and Oxidative Stresses
Inotodiol, a lanostane-type triterpenoid, and many phytochemicals from Chaga mushrooms have been investigated for various allergic diseases. However, the anti-aging and anti-inflammatory activities of inotodiol under different types of oxidative stress and the impact of inotodiol on collagen and hyaluronan synthesis have not been sufficiently studied. Lanostane triterpenoids-rich concentrate, which contained 10% inotodiol as major (inotodiol concentrate), was prepared from Chaga and compared with pure inotodiol in terms of anti-inflammatory activities on a human keratinocyte cell line, HaCaT cells, under various stimulations such as stimulation with ultraviolet (UV) B or tumor necrosis factor (TNF)-α. In stimulation with TNF-α, interleukin (IL)-1β, IL-6, and IL-8 genes were significantly repressed by 0.44~4.0 μg/mL of pure inotodiol. UVB irradiation induced the overexpression of pro-inflammatory cytokines, but those genes were significantly suppressed by pure inotodiol or inotodiol concentrate. Moreover, pure inotodiol/inotodiol concentrate could also modulate the synthesis of collagen and hyaluronic acid by controlling COL1A2 and HAS2/3 expression, which implies a crucial role for pure inotodiol/inotodiol concentrate in the prevention of skin aging. These results illuminate the anti-inflammatory and anti-aging effects of pure inotodiol/inotodiol concentrate, and it is highly conceivable that pure inotodiol and inotodiol concentrate could be promising natural bioactive substances to be incorporated in therapeutic and beautifying applications.
Analysis of Stage-Specific Gene Expression Profiles in the Uterine Endometrium during Pregnancy in Pigs
The uterine endometrium plays a critical role in regulating the estrous cycle and the establishment and maintenance of pregnancy in mammalian species. Many studies have investigated the expression and function of genes in the uterine endometrium, but the global expression pattern of genes and relationships among genes differentially expressed in the uterine endometrium during gestation in pigs remain unclear. Thus, this study investigated global gene expression profiles using microarray in pigs. Diverse transcriptome analyses including clustering, network, and differentially expressed gene (DEG) analyses were performed to detect endometrial gene expression changes during the different gestation stages. In total, 6,991 genes were found to be differentially expressed by comparing genes expressed on day (D) 12 of pregnancy with those on D15, D30, D60, D90 and D114 of pregnancy, and clustering analysis of detected DEGs distinguished 8 clusters. Furthermore, several pregnancy-related hub genes such as ALPPL2, RANBP17, NF1B, SPP1, and CST6 were discovered through network analysis. Finally, detected hub genes were technically validated by quantitative RT-PCR. These results suggest the complex network characteristics involved in uterine endometrial gene expression during pregnancy and indicate that diverse patterns of stage-specific gene expression and network connections may play a critical role in endometrial remodeling and in placental and fetal development to establish and maintenance of pregnancy in pigs.
Optimizing Source-Control Systems for Ammonia Mitigation in Swine Manure Pits: Performance Assessment and Modeling
Ammonia (NH3) emissions from swine manure pits contribute significantly to odor nuisance, health risks, and secondary PM2.5 formation. This study assessed the pilot-scale performance of three source-control technologies: surface sealing with surfactant-based foam system (FOAM SYSTEM), swine manure wiping and removing system (WIPING SYSTEM), and belt-conveyor-based solid–liquid separator system (BELT SYSTEM). Each technology targets a different pathway in the ammonia generation process. The FOAM SYSTEM suppresses volatilization by forming a foam barrier at the air–liquid interface. The WIPING SYSTEM reduces precursor contact time by periodically removing feces. The BELT SYSTEM separates feces and urine upon excretion, inhibiting enzymatic ammonia formation. Among the individual systems, the BELT SYSTEM achieved the highest ammonia reduction efficiency of 91.7%, followed by the FOAM SYSTEM (73.6%) and WIPING SYSTEM (64.4%). The combined FOAM SYSTEM + BELT SYSTEM yielded the best performance with an ammonia reduction efficiency of 94.4%, showing modest synergy without operational interference. In contrast, the FOAM SYSTEM + WIPING SYSTEM configuration achieved 71.1%, slightly lower than the FOAM SYSTEM alone, likely due to foam disruption. Environmental sensitivity tests revealed that higher temperatures and alkaline pH elevated NH3 emissions, whereas systems that maintained near-neutral pH, like the FOAM SYSTEM, demonstrated greater stability. These findings highlight the importance of integrating physical and source-control mechanisms while considering environmental variability for effective on-farm ammonia mitigation.
Dynamic shifts in metabolic demand during myogenic progression in porcine skeletal muscle stem cells
Optimizing the metabolic environment during porcine skeletal muscle stem cells (PSCs) proliferation and differentiation is essential for efficient muscle cell cultivation. This study investigated metabolic shifts during myogenic progression using cells at P1, P3, D1, and D2 for characterization and metabolomic analysis. Cell number increased until P3, and myotubes formed by D2 but detached by D3 in 2D culture. Gene and protein expression analyses confirmed myogenic progression, including increased MYOD and MHC expression. Metabolomic profiling identified 94 intracellular metabolites, with 24 and 17 differentially abundant metabolites (DAMs) in proliferation and differentiation, respectively. Pathway analysis showed that energy production via amino acid metabolism was key to progression. Notably, PSCs relied on glycolysis during proliferation and shifted to mitochondrial oxidative phosphorylation during differentiation. These results highlight stage-specific metabolic reprogramming and provide insights for optimizing culture conditions, offering foundational knowledge to improve the efficiency and quality of cultured meat production.