• ALGAE
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• v.36 no.4
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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.

• BMB Reports
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• v.39 no.1
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• pp.55-60
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• 2006

We describe a phage display strategy, based on the differential resistance of proteins to denaturant-induced unfolding, that can be used to select protein variants with improved conformational stability. To test the efficiency of this strategy, wild-type and two stable variants of ${\alpha}_1$-antitrypsin (${\alpha}_1AT$) were fused to the gene III protein of M13 phage. These phages were incubated in unfolding solution containing denaturant (urea or guanidinium chloride), and then subjected to an unfavorable refolding procedure (dialysis at $37^{\circ}C$). Once the ${\alpha}_1AT$ moiety of the fusion protein had unfolded in the unfolding solution, in which the denaturant concentration was higher than the unfolding transition midpoint ($C_m$) of the ${\alpha}_1AT$ variant, around 20% of the phage retained binding affinity to anti-${\alpha}_1AT$ antibody due to a low refolding efficiency. Moreover, this affinity reduced to less than 5% when 10 mg/mL skimmed milk (a misfolding-promoting additive) was included during the unfolding/refolding procedure. In contrast, most binding affinity (>95%) remained if the ${\alpha}_1AT$ variant was stable enough to resist unfolding. Because this selection procedure does not affect the infectivity of M13, the method is expected to be generally applicable to the high-throughput screening of stable protein variants, when activity-based screening is not possible.

• BMB Reports
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• v.38 no.4
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• pp.432-439
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• 2005

$Ca^{2+}$/calmodulin transduction pathways have been implicated in mediating stress response and tolerance in plants. Here, three genes encoding calmodulin (Cam) members of the EF-hand family of $Ca^{2+}$-binding proteins were identified from Oryza sativa L. databases. Complementary DNA for each of the calmodulin genes, OsCam1, OsCam2, and OsCam3 were sequenced. OsCam1 and OsCam2 encode a conventional 148-amino acid calmodulin protein that contains four characteristic $Ca^{2+}$-binding motifs. OsCam3 encode a similar protein with a 38-amino-acid extension containing a putative prenylation site (CVIL) at the carboxyl terminus. RT-PCR showed that each of the genes is expressed in leaves and roots of 2-week old rice seedlings. By RNA gel blot analysis, OsCam1 mRNA levels strongly increased in response to NaCl, mannitol and wounding treatments. In contrast, OsCam2 mRNA levels were relatively unchanged under all conditions investigated. NaCl treatment and wounding also increased the OsCam3 mRNA level, but in a more transient manner. Our results indicate that although the expression of genes encoding different calmodulin isoforms is ubiquitous, they are differentially regulated by various stress signals. In addition, we have demonstrated that the calcium-channel blocker lanthanum chloride inhibited the induction of OsCam1 gene expression by both NaCl and mannitol treatments. These results suggest that osmotic stress induced expression of OsCam1 gene requires the $[Ca^{2+}]_{cyt}$ elevation that is known to occur in response to these stimuli.

• Korean journal of food and cookery science
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• v.31 no.4
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• pp.405-412
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• 2015

To develop a color stable and fine bamboo leaf powder (BLP) as a functional green biomaterial, bamboo leaf (BL) purchased from Sasa borealis and cultivated in Damyang, Jeonnam was treated with different conditions and BLP was evaluated. The four treatments comprised of boiling in water, in zinc chloride, sodium bicarbonate, and vinegar solutions, BLP4 was treated with 2% $ZnCl_2$ for 1 h, BLP5 was treated with 1% $ZnCl_2$ for 2 h, and BLP6 was treated with 1% $ZnCl_2+10%$ NaCl for 1 h. The particle size distribution, ash content, water binding capacity, and color change after heating in acidic solution were compared to commercial fine green tea (GTP) and bamboo leaf powders (CBLP). The particle size (cumulative 90%) of BLP was finest in BLP4 followed by BLP6 < BLP5 < GTP < CBLP. The water binding capacity of GTP was the highest and that of BLP was negatively correlated with particle size. After heating in acidic solution, the color of commercial GTP and CBLP changed from bright green to olive green, but the treated BLPs remained bright green. Especially, the -a (greenness) values for the commercial powders decreased from 11.2-13.6 to 3.1-3.8, while those of the treated BLPs did not change.

• Molecules and Cells
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• v.44 no.2
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• pp.88-100
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• 2021

Anoctamin 6/TMEM16F (ANO6) is a dual-function protein with Ca2+-activated ion channel and Ca2+-activated phospholipid scramblase activities, requiring a high intracellular Ca2+ concentration (e.g., half-maximal effective Ca2+ concentration [EC50] of [Ca2+]i > 10 μM), and strong and sustained depolarization above 0 mV. Structural comparison with Anoctamin 1/TMEM16A (ANO1), a canonical Ca2+-activated chloride channel exhibiting higher Ca2+ sensitivity (EC50 of 1 μM) than ANO6, suggested that a homologous Ca2+-transferring site in the N-terminal domain (Nt) might be responsible for the differential Ca2+ sensitivity and kinetics of activation between ANO6 and ANO1. To elucidate the role of the putative Ca2+-transferring reservoir in the Nt (Nt-CaRes), we constructed an ANO6-1-6 chimera in which Nt-CaRes was replaced with the corresponding domain of ANO1. ANO6-1-6 showed higher sensitivity to Ca2+ than ANO6. However, neither the speed of activation nor the voltage-dependence differed between ANO6 and ANO6-1-6. Molecular dynamics simulation revealed a reduced Ca2+ interaction with Nt-CaRes in ANO6 than ANO6-1-6. Moreover, mutations on potentially Ca2+-interacting acidic amino acids in ANO6 Nt-CaRes resulted in reduced Ca2+ sensitivity, implying direct interactions of Ca2+ with these residues. Based on these results, we cautiously suggest that the net charge of Nt-CaRes is responsible for the difference in Ca2+ sensitivity between ANO1 and ANO6.

• Journal of Korean Medicine for Obesity Research
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• v.23 no.2
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• pp.69-77
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• 2023

Objectives: Atriplex gmelinii C. A. Meyer is a halophyte belonging to the Chenopodiaceae family, and its young leaves and stems are used as fodder for livestock. The aim of the present study was to investigate the effects of A. gmelinii extract and its solvent fractions on lipid accumulation during adipogenesis of 3T3-L1 preadipocytes. Methods: The samples of A. gmelinii were separately extracted using methylene chloride and methanol. Subsequently, they were combined to formulate the initial extract, which was then partitioned based on polarity to prepare solvent fractions. Oil Red O staining was employed to measure lipid accumulation during the differentiation of 3T3-L1 preadipocytes. To verify cytotoxicity in 3T3-L1 cells, MTT assays were conducted. The expression levels of transcription factors in 3T3-L1 preadipocytes were measured through Western blotting analysis. Results: At 50 ㎍/mL, treatment of A. gmelinii extract and its solvent fractions during the differentiation of 3T3-L1 preadipocytes significantly diminished lipid accumulation with no noteworthy cytotoxicity on cell viability. Additionally, when investigating the biochemical pathways that underlie the prevention of lipid accumulation using solvent fractions, it was found that the n-BuOH and n-hexane fractions significantly decreased the expression of key transcription factors involved in the generation of fat, such as peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), and sterol regulatory element-binding protein-1c (SREBP1c). Conclusions: These findings indicate that A. gmelinii can effectively reduce the accumulation of fat in 3T3-L1 adipocytes, making it a potentially valuable material for mitigating and preventing obesity.

• Journal of Conservation Science
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• v.31 no.2
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• pp.87-94
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• 2015

Plastic artwork can be appeared crack, change of color and whitening event by various environment conditions. A large scale plastic artwork often exhibits in outside it will be directly degraded by physical and chemical degradation factor such as strong sunlight, high humidity and rainfall. We should know degradation characteristic of plastics to prevent these damages. In this study, we studied degradation characteristic of plastics (5 types of wide use plastics; polypropylene, polystyrene, polyethylene, polyvinyl chloride, polyurethane) depending on various artificial degradation conditions such as high temperature, ultraviolet and these complex conditions (high temperature and ultraviolet). As a result, polypropylene, polystyrene and polyethylene show the most visible change especially polypropylene, polystyrene. Polypropylene didn't show a great change degree of tensile strength and contact angle, on the other hand polystyrene did. Polypropylene and polystyrene weakened by photo degradation, polyvinyl chloride and polyurethane had relatively good light stability. Also the high temperature and complex conditions were most degradation characteristic. High temperature worked for degradation catalyst because its energy can not enough worked for cut off binding energy of plastics while ultraviolet condition effected as directly degradation condition. Though following results, we expect it can be applied to investigation of degradation factor depending on plastic artwork materials and basic result of plastic artworks conservation.

• Korean Journal of Biological Psychiatry
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• v.4 no.1
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• pp.102-107
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• 1997

Ginseng root, as a folk medicine, has been used in far eastern countries for thousands of years. Ginseng extract has been shown to have a variety of effects on the activity of the central nervous system, promoting stimulation as well as inhibition of the cortical activity. A survey of the relevant literatures has indicated that the putative anxiolytic activity of red ginseng has not been scientifically investigated. Therefore, the present study was designed to assess anxiolytic effect of gingseng total saponins(GTS). The putative anxiolytic effects of several fractions of GTS were investigated in mice using an elevated plus maze paradigm. Single dose administration of TS Fr.-I showed anxiolytic action in mice. Anxiolytic effect induced by TS Fr.-I was similar to that induced by diazepam. TS Fr.-II, TS Fr.-III and TS Fr.-IV did not show the anxiolytic action compared with that of TS Fr.-I. It was suggested that regulation of GABAergic neurotransmission may be important in the action of GTS. The Interaction of GTS fractions with benzodiazepine receptor was performed using rat cortical membranes. GTS inhibited the binding of [3H] Ro 15-1788 on the benzodiazepine receptor. Among from TS fractions, the binding activity of GTS in the TS Fr.-IV was highest, which did not show the anxiolytic activity. From these results, we conclude that GTS has anxiolytic action, and this is not related to benzodiazepine receptor binding activity.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.84-90
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• 1994

Kinetic parameters of various substrates and inhibitors were measured to elucidate the binding requirements of the active site of intracellular adenosine deaminase (ADA) in Aspergillus oryzae. 3'-Deoxyadenosine was the best substrate according to the value of relative kcat/$K_m$. Purine riboside was found to be the strongest inhibitor with the $K_i$ value of $3.7{\times}10^{-5}$M. Adenine acted neither as a substrate nor as an inhibitor, suggesting the presence of ribose at N-9 of adenosine was crucial to binding. ADA also catalyzed the dechlorination of 6-chloropurine riboside, generating inosine and chloride ions. Substrate specificity of 6-chloropurine riboside was 0.86% of adenosine. Purine riboside, a competitive inhibitor of ADA, inhibit the dechlorination with similar $K_i$ value, suggesting that the same binding site was involved in deamination and dechlorination. Among the sulfhydryl group reagents, mercurials, pchloromercuribenzoate (PCMB), mersalyl acid and $HgCl_2$ inactivated the enzyme. Mersalyl acid-inactivated ADA was reactivated by thiol reagents, but PCMB-inactivated enzyme was not. When ADA was treated with the mercurial reagents, the inhibition constants and inhibition patterns were determined. Each inhibition was competitive with substrate. The $K_i$ values of these mercurial reagents were lower in 10 mM phosphate buffer than in 100 mM phosphate buffer, showing phosphate dependency.

• Journal of Photoscience
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• v.9 no.2
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• pp.335-337
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• 2002

Blue light (BL) induces stomatal opening through activation of H$^{+}$ pump, which creates electrical gradient across the plasma membrane for $K^{+}$ uptake into guard cells. The pump is the plasma membrane H$^{+}$ -ATPase and is activated via phosphorylation of the C-terminus with concomitant binding of the 14-3-3 protein. The opening is initiated by the perception of BL through phototropin (phot), which are recently identified as BL receptors in stomatal guard cells. In this study, we provide the biochemical evidence for phots as BL receptors in stomatal guard cells. vfphot was phosphorylated reversibly by BL, and phosphorylation levels of vfphot increased earlier than those of the plasma membrane W-ATPase. BL-dependent phosphorylations of vfphot and H$^{+}$-ATPase showed similar fluence dependency. Staurosporin, an inhibitor of serine/threonine protein kinase, and diphenyleneiodonium chloride (DPI), an inhibitor of flavoprotein, inhibited BL-dependent phosphorylations of vfphot and H$^{+}$ -ATPase. These results indicate that vfphot acts as a BL-receptor mediating stomatal opening.l opening.