• Journal of Nutrition and Health
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• 제37권3호
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• pp.182-192
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• 2004

Conjugated linoleic acid (CLA) is the mixture of positional and geometric isomers of linoleic acid (LA), which is found abundantly in dairy products and meats. This study was performed to investigate the anticarcinogenic effect of CLA in HepG2 hepatoma cells. HepG2 cell were treated with LA and CLA at the various concentrations of 10, 20, 40, 80 uM each at different incubation times. After each incubation times, cell proliferation, fatty acids incorporation into cell, peroxidation and postaglandin E$_2$ (PGE$_2$) and thromboxane $A_2$ (TXA$_2$) for the eicosanoid metabolism were measured. LA treated HepG2 cells were increased cell growth 6 - 70％ of control whereas CLA increased cell death the half of those in LA group (p 〈 0.001). LA and CLA were incorporated very well into the cellular membranes four times higher than in control according to concentration and longer incubation times. Moreover, LA synthesized significantly arachidonic acids corresponding with LA concentration compared to CLA supplementation. The supplementation with LA increased intracellular lipid peroxides concentration corresponding with LA concentration and five times higher than those in CLA significantly at any incubation times (p 〈 0.001). PGE$_2$ and TXA$_2$ levels were three to twenty times lower in condition of CLA treatments than LA, respectively. Overall, the dietary CLA might change the HepG2 cell growth by the changes of cell composition, production of lipid peroxide. Since CLA have not changed the levels of arachidonic acid of cell membrane, which was sources of eicosanoids, eicosanoid synthesis was not increased in CLA compared to LA. Our results was suggest CLA has a possibility to protect the progress of atherosclerosis because CLA does not produce lipid production and endothelial contraction factors in liver.

• Journal of Korean Neurosurgical Society
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• 제38권6호
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• pp.456-464
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• 2005

Objective : The authors investigated whether rotenone induces cellular death also in non-dopaminergic neurons and high concentration of potassium ion can show protective effect for non-dopaminergic neuron in case of rotenone-induced cytotoxicity. Methods : Neuro 2A cells was treated with rotenone, and their survival as well as cell death mechanism was estimated using 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium[MTT] assay, Lactate dehydrogenase[LDH] release assay, fluorescence microscopy, and agarose gel electrophoresis. The changes in rotenone-treated cells was also studied after co-treatment of 50mM KCl. And the protective effect of KCl was evaluated by mitochondrial membrane potential assay and compared with the effects of various antioxidants. Results : Neuro 2A cells treated with rotenone underwent apoptotic death showing chromosome condensation and fragmentation as well as DNA laddering. Co-incubation of neuro 2A cells with 50mM KCl prevented it from the cytotoxicity induced by rotenone. Intracellular accumulation of reactive oxygen species[ROS] resulting by rotenone were significantly reduced by 50mM KCl. Potassium exhibited significantly similar potency compared to the antioxidants. Conclusion : The present findings showed that potassium attenuated rotenone-induced cytotoxicity, intracellular accumulation of ROS, and fragmentation of DNA in Neuro 2A cells. These findings suggest the therapeutic potential of potassium ion in neuronal apoptosis, but the practical application of high concentration of potassium ion remains to be settled.

• Biomolecules & Therapeutics
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• 제27권6호
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• pp.562-569
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• 2019

Niacinamide (NIA) is a water-soluble vitamin that is widely used in the treatment of skin diseases. Moreover, NIA displays antioxidant effects and helps repair damaged DNA. Recent studies showed that particulate matter 2.5 ($PM_{2.5}$) induced reactive oxygen species (ROS), causing disruption of DNA, lipids, and protein, mitochondrial depolarization, and apoptosis of skin keratinocytes. Here, we investigated the protective effects of NIA on $PM_{2.5}$-induced oxidative stress in human HaCaT keratinocytes. We found that NIA could inhibit the ROS generation induced by $PM_{2.5}$, as well block the $PM_{2.5}$-induced oxidation of molecules, such as lipids, proteins, and DNA. Furthermore, NIA alleviated $PM_{2.5}$-induced accumulation of cellular $Ca^{2+}$, which caused cell membrane depolarization and apoptosis, and reduced the number of apoptotic cells. Collectively, the findings show that NIA can protect keratinocytes from $PM_{2.5}$-induced oxidative stress and cell damage.

• 통합자연과학논문집
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• 제7권1호
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• pp.25-38
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• 2014

Amyloid-${\beta}$-peptide ($A{\beta}$) is important in the pathogenesis of Alzheimer's disease (AD). Calpain ($Ca^{2+}$-dependent protease) and caspase-8 (the initiating caspase for the extrinsic, receptor-mediated apoptosis pathway) have been implicated in $AD/A{\beta}$ toxicity. We found that $A{\beta}$ promoted degradation of calpastatin (the specific endogenous calpain inhibitor); calpastatin degradation was prevented by inhibitors of either calpain or caspase-8. The results implied a cross-talk between the two proteases and suggested that one protease was responsible for the activity of the other one. In neuron-like differentiated PC12 cells, calpain promotes active caspase-8 formation from procaspase-8 via the $A{\beta}$ and CD95 pathways, along with degradation of the procaspase-8 processing inhibitor caspase-8 (FLICE)-like inhibitory protein, short isoform (FLIPS). Inhibition of calpain (by pharmacological inhibitors and by overexpression of calpastatin) prevents the cleavage of procaspase-8 to mature, active caspase-8, and inhibits FLIPS degradation in the $A{\beta}$-treated and CD95-triggered cells. Increased cellular Ca2+ per se results in calpain activation but does not lead to caspase-8 activation or FLIPS degradation. The results suggest that procaspase-8 and FLIPS association with cell membrane receptor complexes is required for calpain-induced caspase-8 activation. The results presented here add to the understanding of the roles of calpain, caspase- 8, and CD95 pathway in $AD/A{\beta}$ toxicity. Calpain-promoted activation of caspase-8 may have implications for other types of CD95-induced cell damage, and for nonapoptotic functions of caspase-8. Inhibition of calpain may be useful for modulating certain caspase-8-dependent processes.

• Animal cells and systems
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• 제11권1호
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• pp.39-50
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• 2007

Tau plays a role in numerous neuronal processes, such as vesicle transport, microtubule-plasma membrane interaction and intracellular localization of proteins. SUMO (Small Ubiquitin-like Modifier) modification (SUMOylation) appears to regulate diverse cellular processes including nuclear transport, signal transduction, apoptosis, autophagy, cell cycle control, ubiquitin-dependent degradation, as well as gene transcription. We noticed that putative SUMOylation site is localized at $^{340}K$ of $Tau(^{339}VKSE^{342})$ with the consensus sequence information (${\Phi}KxE$ ; where ${\Phi}$ represents L, I, V or F and x is any amino acid). In this report, we demonstrated that $^{340}K$ of Tau is the SUMOylation site and that a point mutant of Tau S214E (an analog of the phospho $^{214}S$ Tau) promotes its SUMOylation at $^{340}K$ and its nuclear or nuclear vicinity localization, by co-immunoprecipitation and confocal microscopy analysis. Further, we demonstrate that the Tau S214E (neither Tau S214A nor Tau K340R) mutant increases its protein stability. However, the SUMOylation at $^{340}K$ of Tau did not influence cell survival, as determined by FACS analysis. Therefore, our results suggested that the phosphorylation of Tau on $^{214}S$ residue promotes its SUMOylation on $^{340}K$ residue and nuclear vicinity localization, and increases its stability, without influencing cell survival.

• Molecules and Cells
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• 제44권9호
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• pp.637-646
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• 2021

Free fatty acids are converted to acyl-CoA by long-chain acyl-CoA synthetases (ACSLs) before entering into metabolic pathways for lipid biosynthesis or degradation. ACSL family members have highly conserved amino acid sequences except for their N-terminal regions. Several reports have shown that ACSL1, among the ACSLs, is located in mitochondria and mainly leads fatty acids to the β-oxidation pathway in various cell types. In this study, we investigated how ACSL1 was localized in mitochondria and whether ACSL1 overexpression affected fatty acid oxidation (FAO) rates in C2C12 myotubes. We generated an ACSL1 mutant in which the N-terminal 100 amino acids were deleted and compared its localization and function with those of the ACSL1 wild type. We found that ACSL1 adjoined the outer membrane of mitochondria through interaction of its N-terminal region with carnitine palmitoyltransferase-1b (CPT1b) in C2C12 myotubes. In addition, overexpressed ACSL1, but not the ACSL1 mutant, increased FAO, and ameliorated palmitate-induced insulin resistance in C2C12 myotubes. These results suggested that targeting of ACSL1 to mitochondria is essential in increasing FAO in myotubes, which can reduce insulin resistance in obesity and related metabolic disorders.

• Animal Bioscience
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• 제34권9호
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• pp.1525-1531
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• 2021

Objective: The objective of this study was to evaluate the antimicrobial effects of fermented Maillard reaction products made by milk proteins (FMRPs) on Clostridium perfringens (C. perfringens), and to elucidate antimicrobial modes of FMRPs on the bacteria, using physiological and morphological analyses. Methods: Antimicrobial effects of FMRPs (whey protein plus galactose fermented by Lactobacillus rhamnosus [L. rhamnosus] 4B15 [Gal-4B15] or Lactobacillus gasseri 4M13 [Gal-4M13], and whey protein plus glucose fermented by L. rhamnosus 4B15 [Glc-4B15] or L. gasseri 4M13 [Glc-4M13]) on C. perfringens were tested by examining growth responses of the pathogen. Iron chelation activity analysis, propidium iodide uptake assay, and morphological analysis with field emission scanning electron microscope (FE-SEM) were conducted to elucidate the modes of antimicrobial activities of FMRPs. Results: When C. perfringens were exposed to the FMRPs, C. perfringens cell counts were decreased (p<0.05) by the all tested FMRPs; iron chelation activities by FMRPs, except for Glc-4M13. Propidium iodide uptake assay indicate that bacterial cellular damage increased in all FMRPs-treated C. perfringens, and it was observed by FE-SEM. Conclusion: These results indicate that the FMRPs can destroy C. perfringens by iron chelation and cell membrane damage. Thus, it could be used in dairy products, and controlling intestinal C. perfringens.

• ALGAE
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• 제36권4호
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• pp.315-326
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• 2021

Ion channels are membrane protein complexes mediating passive ion flux across the cell membranes. Every organism has a certain set of ion channels that define its physiology. Dinoflagellates are ecologically important microorganisms characterized by effective physiological adaptability, which backs up their massive proliferations that often result in harmful blooms (red tides). In this study, we used a bioinformatics approach to identify homologs of known ion channels that belong to 36 ion channel families. We demonstrated that the versatility of the dinoflagellate physiology is underpinned by a high diversity of ion channels including homologs of animal and plant proteins, as well as channels unique to protists. The analysis of 27 transcriptomes allowed reconstructing a consensus ion channel repertoire (channelome) of dinoflagellates including the members of 31 ion channel families: inwardly-rectifying potassium channels, two-pore domain potassium channels, voltage-gated potassium channels (K_v), tandem K_v, cyclic nucleotide-binding domain-containing channels (CNBD), tandem CNBD, eukaryotic ionotropic glutamate receptors, large-conductance calcium-activated potassium channels, intermediate/small-conductance calcium-activated potassium channels, eukaryotic single-domain voltage-gated cation channels, transient receptor potential channels, two-pore domain calcium channels, four-domain voltage-gated cation channels, cation and anion Cys-loop receptors, small-conductivity mechanosensitive channels, large-conductivity mechanosensitive channels, voltage-gated proton channels, inositole-1,4,5-trisphosphate receptors, slow anion channels, aluminum-activated malate transporters and quick anion channels, mitochondrial calcium uniporters, voltage-dependent anion channels, vesicular chloride channels, ionotropic purinergic receptors, animal volage-insensitive cation channels, channelrhodopsins, bestrophins, voltage-gated chloride channels H⁺/Cl^- exchangers, plant calcium-permeable mechanosensitive channels, and trimeric intracellular cation channels. Overall, dinoflagellates represent cells able to respond to physical and chemical stimuli utilizing a wide range of G-protein coupled receptors- and Ca²⁺-dependent signaling pathways. The applied approach not only shed light on the ion channel set in dinoflagellates, but also provided the information on possible molecular mechanisms underlying vital cellular processes dependent on the ion transport.

• Journal of Ginseng Research
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• 제43권3호
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• pp.431-441
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• 2019

Background: The efficacy of ginseng, the representative product of Korea, and its chemical effects have been well investigated. The ginsenoside RG3 has been reported to exhibit apoptotic, anticancer, and antidepressant-like effects. Methods: In this report, the putative effect of RG3 on several cellular function including cell survival, differentiation, development and aging process were evaluated by monitoring each specific marker. Also, mitochondrial morphology and function were investigated in ultraviolet (UV)-irradiated normal human dermal fibroblast cells. Results: RG3 treatment increased the expression of extracellular matrix proteins, growth-associated immediate-early genes, and cell proliferation genes in UV-irradiated normal human dermal fibroblast cells. And, RG3 also resulted in enhanced expression of antioxidant proteins such as nuclear factor erythroid 2-related factor-2 and heme oxygenase-1. In addition, RG3 affects the morphology of UV-induced mitochondria and plays a role in protecting mitochondrial dysfunction. Conclusioin: RG3 restores mitochondrial adenosine triphosphate (ATP) and membrane potential via its antioxidant effects in skin cells damaged by UV irradiation, leading to an increase in proteins linked with the extracellular matrix, cell proliferation, and antioxidant activity.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.141-150
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• 2019

The spatial landmark protein Bud8 plays a crucial role in bipolar budding in the budding yeast Saccharomyces cerevisiae. The unconventional yeast Yarrowia lipolytica can also bud in a bipolar pattern, but is evolutionarily distant from S. cerevisiae. It encodes the protein YALI0F12738p, which shares the highest amino acid sequence homology with S. cerevisiae Bud8, sharing a conserved transmembrane domain at the C-terminus. Therefore, we named it YlBud8. Deletion of YlBud8 in Y. lipolytica causes cellular separation defects, resulting in budded cells remaining linked with one another as cell chains or multiple buds from a single cell, which suggests that YlBud8 may play an important role in cell separation, which is distinct from the function of Bud8 in S. cerevisiae. We also show that the YlBud8-GFP fusion protein is located at the cell membrane and enriched in the bud cortex, which would be consistent with a role in the regulation of cell separation. The coiled-coil domain at the N-terminus of YlBud8 is important to the correct localization and function of YlBud8, as truncated proteins that do not contain the coiled-coil domain cannot rescue the defects observed in $Ylbud8{\Delta}$. This finding suggests that a new signaling pathway controlled by YlBud8 via regulation of cell separation may exist in Y. lipolytica.