Hyung-Kyoon Choi's research while affiliated with Chung-Ang University and other places

Publications (199)

Article
Lung cancer has the highest incidence and mortality rates among all types of cancer worldwide, and 80%–85% of patients with lung cancer are diagnosed with non‐small cell lung cancer (NSCLC), which has 5‐year survival rate of only 5% at advanced stages. Development of new therapeutic agents and strategies is required to enhance the treatment efficie...
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Cyanobacteria are a compelling biochemical production platform for their ability to propagate using light and atmospheric CO 2 via photosynthesis. However, the engineering of strains is hampered by limited understanding of photosynthesis under diverse environmental conditions such as high-light and low-temperature stresses.
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Duckweeds are floating plants of the family Lemnaceae , comprising 5 genera and 36 species. They typically live in ponds or lakes and are found worldwide, except the polar regions. There are two duckweed subfamilies — namely Lemnoidea and Wolffioideae , with 15 and 21 species, respectively. Additionally, they have characteristic reproduction method...
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To provide preliminary insights into metabolic and lipidomic characteristics in radioresistant triple-negative breast cancer (TNBC) cells and suggest potential therapeutic targets, we performed a comprehensive metabolic and lipidomic profiling of radioresistant MDA-MB-231 (MDA-MB-231/RR) TNBC cells and their parental cells using gas chromatography-...
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Among essential phytohormones playing a pivotal role in regulating growth and development, ortho-topolin riboside (oTR) exerts the most substantial anti-tumor potency in various cancer cell lines. This study was designed to establish a quantitative determination method for oTR in mouse plasma using high-performance liquid chromatography coupled wit...
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SQCC is a major type of NSCLC, which is a major cause of cancer-related deaths, and there were no reports regarding the prediction of metastatic potential of lung SQCC by metabolomic and lipidomic profiling. In this study, metabolomic and lipidomic profiling of lung SQCC were performed to predict its metastatic potential and to suggest potential th...
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Biodiesel contains methyl or ethyl esters of long-chain fatty acids and has recently attracted increasing attention. Microalgae have emerged as a sustainable biodiesel production system owing to their photosynthetic potential. However, the conversion of microalgal biomass to biodiesel requires high energy and is costly. This study aimed to overcome...
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Cyanobacteria are considered as promising microbial cell factories producing a wide array of bio-products. Among them, Synechocystis sp. PCC 7338 has the advantage of growing in seawater, rather than requiring arable land or freshwater. Nonetheless, how this marine cyanobacterium grows under the high salt stress condition remains unknown. Here, we...
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The precise determination of the chemical composition in crops is important to identify their nutritional and functional value. The current study performed a systematic delineation of the rice metabolome, an important staple in Asia, to investigate the following: (1) comparative features between brown and white rice; (2) variety-specific compositio...
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Sesame (Sesamum indicum) is one of the most widely cultivated crops in Asia and Africa. The identification of the geographical origins of sesame seeds is important for the detection of fraudulent samples. This study was conducted to build a prediction model and suggest potential biomarkers for distinguishing the geographical origins of sesame seeds...
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With the increase in soybean trade between countries, the intentional mislabeling of the origin of soybeans has become a serious problem worldwide. In this study, metabolic profiling of soybeans from the Republic of Korea and China was performed by nuclear magnetic resonance (NMR) spectroscopy coupled with multivariate statistical analysis to predi...
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Synechocystis strains are cyanobacteria that can produce useful biomaterials for biofuel and pharmaceutical resources. In this study, the effects of exogenous glucose (5-mM) on cell growth, photosynthetic pigments, metabolites, and lipids in Synechocystis sp. PCC 7338 (referred to as Synechocystis 7338) were investigated. Exogenous glucose increase...
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Synechocystis sp. PCC 7338 (hereafter referred to as Synechocystis 7338) is a marine cyanobacterium that has the potential to produce photosynthetic pigments. In this study, we investigated the effects of various NaCl concentrations (0, 0.4, 0.8, and 1.2 M) on cell growth, photosynthetic pigments, and metabolites and intact lipid species profiles i...
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Cyanobacteria, given their ability to produce various secondary metabolites utilizing solar energy and carbon dioxide, are a potential platform for sustainable production of biochemicals. Until now, conventional metabolic engineering approaches have been applied to various cyanobacterial species for enhanced production of industrially valued compou...
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Freshwater Synechocystis sp. PCC 6803 has been considered to be a platform for the production of the next generation of biofuels and is used as a model organism in various fields. Various genomics, transcriptomics, metabolomics, and proteomics studies have been performed on this strain, whereas marine Synechocystis sp. PCC 7338 has not been widely...
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Sesame seeds are an oil crop mainly cultivated in Asian and African countries. Identification of the geographical origin of sesame seeds is an important issue for preventing adulteration and for quality assurance. This study was performed to establish a discrimination model and investigate potential biomarkers for differentiating the geographical o...
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Fermented vegetable juices have gained attention due to their various beneficial effects on human health. In this study, we employed gas chromatography–mass spectrometry, direct infusion-mass spectrometry, and liquid chromatography–mass spectrometry to identify useful metabolites, lipids, and carotenoids in vegetable juice (VJ) fermented with Lacto...
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Lemna species have been used in the food, feed, and pharmaceutical industries, as they are inexpensive sources of proteins, starches, and fatty acids. In this study, we treated L. paucicostata with different concentrations (0.05, 0.1, 0.2, 0.5, or 1 mM) of ethephon. The total dry weight decreased in all ethephon-treated groups compared to the contr...
Article
Nutrition-compositional evaluation is critical for quality control and value determination of agricultural products. Sesame seed is an important crop worldwide, enriched with primary nutrients and bioactive compounds. Here, we metabo-typed sesame seeds cultivated in Korea (N = 20) and imported from China (N = 11), South Asia (India and Pakistan), a...
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Background: Gut microbiota are known to be closely related to irritable bowel syndrome (IBS). However, not much is known about characteristic fecal metabolic profiles of IBS. We aimed to characterize fecal metabolites in patients with IBS with predominant diarrhea (IBS-D) using 1 H-nuclear magnetic resonance (1 H-NMR) spectroscopy. Methods: In t...
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Synechocystis strains are considered as valuable resources for production of useful metabolites. Comparative primary metabolic and lipidomic profiling of freshwater and marine Synechocystis strains is needed to understand the physiological characteristics of each strain at molecular level. In this study, we performed comparative primary metabolic a...
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Amiodarone is known to induce hepatic injury in some recipients. We applied an untargeted metabolomics approach to identify endogenous metabolites with potential as biomarkers for amiodarone-induced liver injury. Oral amiodarone administration for 1 week in rats resulted in significant elevation of acylcarnitines and phospholipids in the liver. Hep...
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The study of metabolomics in natural products using the diverse analytical instruments including GC-MS, LC-MS, and NMR is useful for the exploration of physiological and biological effects and the investigation of drug discovery and health functional foods. Cordyceps militaris has been very attractive to natural medicine as one of traditional Chine...
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Human breast cancer cell line, MDA-MB-231, is highly invasive and aggressive, compared to less invasive cell line, MCF-7. To explore the genes that might influence the malignancy of MDA-MB-231, DNA microarray analysis was performed. The results showed that G0/G1 switch 2 (G0S2) was one of the most highly expressed genes among the genes upregulated...
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The rapid and reproducible preparation of biological samples is an essential requirement for LC-MS-based clinical metabolomics profiling. Herein, we proposed a novel, automated sample preparation method for serum metabolite LC-MS analysis. This method included a one-step double-filtration process with two filters (30K and 10K MWCO). High sample thr...
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It is necessary to characterize and classify neural stem cells (NSCs) and differentiated cells (DCs) for potential use of NSC to treat neurodegenerative diseases. We therefore performed an analysis of NSCs and DCs using gas chromatography mass spectrometry (GC-MS) and direct infusion mass spectrometry (DI-MS) with elaborate multivariate statistical...
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This study presents the impacts of TiO2 nanoparticles (TNPs) amendment on plant growth, phosphorus (P) content, and dissolved organic matter (DOM) composition in the rhizosphere. For this work, wheat plants (Galaxy-2013) were exposed to soil amended by different amounts of TNPs (i.e., 0, 50, and 100 mg TNP/kg of soil) for 40 days and harvested. The...
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It is generally assumed that each organism has evolved to possess a unique ribosomal RNA (rRNA) species optimal for its physiological needs. However, some organisms express divergent rRNAs, the functional roles of which remain unknown. Here, we show that ribosomes containing the most variable rRNAs, encoded by the rrnI operon (herein designated as...
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Melanoma is the most aggressive form of skin cancer, with metastatic melanoma being refractory to currently available conventional therapies. In this study, we evaluated the inhibitory effect of coronatine (COR) on the proliferation of metastatic melanoma cells. COR inhibited the proliferation of melanoma cells but negligibly affected the prolifera...
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Classification and characterization of agricultural products at molecular levels are important but often impractical with genotyping, particularly for soybeans that have numerous types of variety and landraces. Alternatively, metabolic signature, a determinant for nutritional value, can be the good molecular indicator, which reflects cultivation re...
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Unprecedent usage of nanoparticles (NPs) over very large scale has raised concerns about their release into agro-environments. The effects of these emerging pollutants on staple food crops and contrasted soils are not very well documented. The main aim of present work was to investigate the exposure–response of 10 wheat cultivars to titanium dioxid...
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Cordyceps militaris is a species of Cordyceps that is classified in the Cordycipitaceae family and is well known in East Asia as a traditional medicinal mushroom. Its artificial fruit body has been widely cultivated for commercial use in cosmetics, functional food, and medicine. To explore the metabolites associated with fruit body development, we...
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We conducted in vitro assays to investigate the antioxidant properties of aqueous or ethanolic extracts of roasted rice hulls. Phenolic compound contents were analyzed via HPLC, and comprehensive chemical profiles were obtained via ¹H NMR and ¹H-H COSY NMR. Rice hulls were roasted at 150, 180, and 230 °C for 20 min, after which the aqueous and 70%...
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This study aimed to improve the production of phycobiliproteins using TiO2 nanoparticles (NPs) in Synechocystis sp. PCC 6803. The growth characteristics of Synechocystis cells were not affected by TiO2 NPs treatment, but this treatment increased the chlorophyll content significantly by 62.2% (14.6 mg/L) compared to that of control (9.0 mg/L) on day...
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The intestinal microflora plays important roles in the health of the host, such as nutrient processing and the modulation of intestinal immune responses. The constituents of the diet greatly affect the composition of the microbiota and its metabolites. The human intestinal microbiota is made up of around 100 trillion microbial cells encompassing at...
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The ability to determine the origin of soybeans is an important issue following the inclusion of this information in the labeling of agricultural food products becoming mandatory in South Korea in 2017. This study was carried out to construct a prediction model for discriminating Chinese and Korean soybeans using Fourier-transform infrared (FT-IR)...
Data
The provinces, cities, and geographic coordinates of soybean samples harvested in 2016 from Republic of Korea and China. (DOCX)
Article
The ability to determine the origin of soybeans is an important issue following the inclusion of this information in the labeling of agricultural food products becoming mandatory in South Korea in 2017. This study was carried out to construct a prediction model for discriminating Chinese and Korean soybeans using Fourier-transform infrared (FT-IR)...
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The effects of agitating culture conditions on the growth, metabolic and carotenoid profiles of Lemna paucicostata were investigated in this study using gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry. Lemna paucicostata cultivated under static and agitating conditions showed no significant difference in total plant...
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The images for Figs 4 and 5 are incorrectly switched. The image that appears as Fig 4 should be Fig 5, and the image that appears as Fig 5 should be Fig 4. The figure captions appear in the correct order. Please see the corrected Fig 4 and Fig 5 below.[Figure Presented]. © 2018 Song et al. This is an open access article distributed under the terms...
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Ginseng (Panax ginseng) is recognized as one of the most valuable medicinal herbs in Asia and it contains diverse phytochemicals that contribute to its pharmacological effects. Although lipids represent a major component of ginseng, ginseng lipids are still far from being fully explored. This review is focused on ginseng lipid components and method...
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RNase E has a pivotal role in the degradation and processing of RNAs in Escherichia coli, and protein inhibitors RraA and RraB control its enzymatic activity. The halophilic pathogenic bacterium Vibrio vulnificus also expresses orthologs of RNase E and RraA—RNase EV, RraAV1, and RraAV2 (herein renamed as VvRNase E, VvRraA1, and VvRraA2). A previous...
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Lipids in microalgae are energy-rich compounds and considered as an attractive feedstock for biodiesel production. To redirect carbon flux from competing pathways to the fatty acid synthesis pathway of Tetraselmis sp., we used three types of chemical inhibitors, which can block the starch synthesis pathway or photorespiration, under nitrogen-suffic...
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Circulating tumor cells (CTCs) are essential for the establishment of distant metastasis. Numerous studies have characterized CTCs as metastatic precursors; however, the molecular nature of CTCs has not been completely revealed yet due to the low number of CTCs in the blood stream. As an alternative approach, we developed a long-term suspension cel...
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Malignant melanoma, characterized by its ability to metastasize to other organs, is responsible for 90% of skin cancer mortality. To investigate alterations in the cellular metabolome and lipidome related to melanoma metastasis, gas chromatography-mass spectrometry (GC-MS) and direct infusion-mass spectrometry (DI-MS)-based metabolic and lipidomic...
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In this study, the effects of coronatine treatment on the growth, comprehensive metabolic profiles, and productivity of bioactive compounds, including phenolics and phytosterols, in whole plant cultures of Lemna paucicostata were investigated using gas chromatography-mass spectrometry (GC-MS) coupled with multivariate statistical analysis. To deter...
Data
Growth curve of L. paucicostata grown under control and coronatine treatment. Data are mean values, and the vertical bars indicate the standard deviation from four biological replications. (TIF)
Data
P-values for post hoc comparisons between groups of L. paucicostata using the Mann-Whitney test at p = 0.017 significance level according to Bonferroni's method. G1, G2, and G3 present three groups (control: G1, coronatine treatment at day 0: G2, and day 23: G3) on day 27, and G4, G5, and G6 present three groups (control: G4, coronatine treatment a...
Data
Fronds number of L. paucicostata cultured by coronatine treatment. The fronds number of the whole Lemna paucicostata plants at day 27 and 32 under control and day 23 (COR23) and day28 (COR28) under coronatine treatment. Bars indicate the mean values, and the error bars indicate the standard deviation (n = 4). Significant differences from the contro...
Data
Metabolic profiles of phenylpropanoid pathway of L. paucicostata cultured by coronatine treatment. Metabolic changes of L. paucicostata among three groups (control, coronatine treatment at day 0, and day 23) on day 27 are presented in upper graphs, and metabolic changes of L. paucicostata among three groups (control, coronatine treatment at day 0,...
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Metabolites list according to MSI (The Metabolomics Standards Initiative) criterion. (DOCX)
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External appearance characteristics of Panax ginseng ‘Yunpoong’ sample with different parts used in this study. Panax ginseng is composed of three parts. (TIF)
Data
PLS-DA model parameters according to the number of components (one to three components), normalization (area, minimum–maximum, and vector normalization), and scaling methods (unit variance and pareto) for differentiation of cultivation ages of Panax ginseng using rhizome (RH). For vector normalization, first and second differentiations were applied...
Data
Score plot derived from PLSR model of 5-year-old Panax ginseng based on variables with VIP values over 1.5 (A), permutation testing plot (B), and correlation plot using training set (C) and test set (D). First differentiation, vector normalization, and unit variance scaling were used in FT-IR spectrum. PLSR, partial least squares regression; VIP, v...
Data
List of permutation parameters obtained by variables selected by various variable influence on projection (VIP) cutoff values and scaling methods. Area normalization and three PLS components were used for discriminating ginseng samples from three parts (tap root, rhizome, lateral root). TR, tap root; RH, rhizome; LR, lateral root; RMSEE, root mean...
Data
PLS-DA model parameters according to the number of components (one to three components), normalization (area, minimum-maximum, and vector normalization), and scaling methods (unit variance and pareto) for differentiation of ginseng parts using 6-year-old Panax ginseng. For vector normalization, first and second differentiations were applied. PLS-DA...
Data
Score plot derived from PLSR model of 6-year-old Panax ginseng based on variables with VIP values over 1.3 (A), permutation testing plot (B), and correlation plot using training set (C) and test set (D). Second differentiation, vector normalization, and pareto scaling were used in FT-IR spectrum. PLSR, partial least squares regression; VIP, variabl...
Data
List of permutation parameters obtained by variables selected by various variable influence on projection (VIP) cutoff values and scaling methods. Vector normalization after second differentiation and two PLS components were used for discriminating ginseng samples from three parts (tap root, rhizome, lateral root). TR, tap root; RH, rhizome; LR, la...
Data
List of permutation parameters obtained by variables selected by various variable influence on projection (VIP) cutoff values and scaling methods. Minimum-maximum normalization and two PLS components were used for discriminating between 5- and 6-year-old ginseng samples. TR, tap root; RH, rhizome; LR, lateral root; RMSEE, root mean squared error of...
Data
PLS-DA model parameters according to the number of components (one to three components), normalization (area, minimum–maximum, and vector normalization) and scaling methods (unit variance and pareto) for differentiation of cultivation ages of Panax ginseng using tap root (TR). For vector normalization, first and second differentiations were applied...
Data
List of permutation parameters obtained by variables selected by various variable influence on projection (VIP) cutoff values and scaling methods. Minimum–maximum normalization and three PLS components were used for discriminating ginseng samples from three parts (tap root, rhizome, lateral root). TR, tap root; RH, rhizome; LR, lateral root; RMSEE,...
Data
List of permutation parameters obtained by variables selected by various variable influence on projection (VIP) cutoff values and scaling methods. Vector normalization after first differentiation and one PLS component were used for discriminating between 5- and 6-year-old ginseng samples. TR, tap root; RH, rhizome; LR, lateral root; RMSEE, root mea...