• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.836-844
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• 2009

A denitrification bacterium was isolated from riverbed soil and identified as Ochrobactrum sp., whose specific enzymes for denitrification metabolism were biochemically assayed or confirmed with specific coding genes. The denitrification activity of strain G3-1 was proportional to glucose/nitrate balance, which was consistent with the theoretical balance (0.5). The modified graphite felt cathode with neutral red, which functions as a solid electron mediator, enhanced the electron transfer from electrode to bacterial cell. The porous carbon anode was coated with a ceramic membrane and cellulose acetate film in order to permit the penetration of water molecules from the catholyte to the outside through anode, which functions as an air anode. A non-compartmented electrochemical bioreactor (NCEB) comprised of a solid electron mediator and an air anode was employed for cultivation of G3-1 cells. The intact G3-1 cells were immobilized in the solid electron mediator, by which denitrification activity was greatly increased at the lower glucose/nitrate balance than the theoretical balance (0.5). Metabolic stability of the intact G3-1 cells immobilized in the solid electron mediator was extended to 20 days, even at a glucose/nitrate balance of 0.1.

• Journal of Photoscience
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• v.4 no.1
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• pp.23-30
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• 1997

Leaf movements in nyctinastic plants are produced by changes in the turgor of extensor and flexor cells, collectively called motor cells, in opposing regions of the leaf movement organ, the pulvinus. In Samanea saman, a tropical tree of the legume family, extensor cells shrink and flexor cells swell to bend the pulvinus and fold the leaf at night, whereas extensor cells swell and flexor cells shrink to straighten the pulvinus and extend the leaf in the daytime. These changes are caused by ion fluxes primarily of potassium and chloride, across the plasma membrane of the motor cells. These ion fluxes are regulated by exogenous light signals and an endogenous biolgical clock. Inward-directed K$^+$ channels are closed in extensor and open in flexor cells in the dark period, while these channels are open in extensor and closed in flexor cells in the light period. Blue light opens the closed K$^+$ channels in extensor and closes the open them in flexor cells during darkness. Illumination of red light followed by darkness induces to open the closed K$^+$ channels in flexor and to close the open K$^+$ channels in extensor cells in the light. The dynamics of K$^+$ channels in motor cells that are controlled by light signals are consistent with the behavior of the pulvini in intact plants. Therefore, these cell types are an attractive model system to elucidate regulations of ion transports and their signal transduction pathways in plants. This review is focused on light-controlled ion movements and regulatory mechanisms involved in phosphoinositide signaling in leaf movements in nyctinastic plants.

• Mycobiology
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• v.51 no.5
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• pp.273-280
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• 2023

The nucleolus is the largest, membrane-less organelle within the nucleus of eukaryotic cell that plays a critical role in rRNA transcription and assembly of ribosomes. Recently, the nucleolus has been shown to be implicated in an array of processes including the formation of signal recognition particles and response to cellular stress. Such diverse functions of nucleolus are mediated by nucleolar proteins. In this study, we characterized a gene coding a putative protein containing a nucleolar localization sequence (NoLS) in the rice blast fungus, Magnaporthe oryzae. Phylogenetic and domain analysis suggested that the protein is orthologous to Rrp8 in Saccharomyces cerevisiae. MoRRP8-GFP (translational fusion of MoRRP8 with green fluorescence protein) co-localizes with a nucleolar marker protein, MoNOP1 fused to red fluorescence protein (RFP), indicating that MoRRP8 is a nucleolar protein. Deletion of the MoRRP8 gene caused a reduction in vegetative growth and impinged largely on asexual sporulation. Although the asexual spores of DMorrp8 were morphologically indistinguishable from those of wild-type, they showed delay in germination and reduction in appressorium formation. Our pathogenicity assay revealed that the MoRRP8 is required for full virulence and growth within host plants. Taken together, these results suggest that nucleolar processes mediated by MoRRP8 is pivotal for fungal development and pathogenesis.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.694-702
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• 1995

Using the Korean red ginseng saponin, which is known to world-wide and thd effects of it have been investigated by many reserachers for years. Ginseng saponin, one of the major components of Korea ginseng root, has many various biologic effects, such as cytotoxic effect, tumorcidal activity, protein biosynthesis and membrane modifying effect. The purpose of this study was to evaluate effects of ginseng saponin on the alkaline phosphatase activity of ROS cells in culture. After ROS cells were seeded into a 96-well plate, 96-well plate cultured until confluence was obtained. To evaluate cytotoxic effect of total saponin in cultured ROS cells, the plates were added to each total saponin concentration (0-1mg/ml). After 48hr., cells were counted by stain with 0.2% trypan blue at randomly selected field microscopically. Also, to evaluate alkaline phosphatase(ALP) activity of total saponin in cultured ROS cell, the plate was added to each total saponin concentration (0-1mg/ml) and ALP activity was assayed. To evaluate time-course of ALP activity, $31.25{\mu}g/ml$ of saponin added to 96-well plate. After culture of 6, 12, 24 and 48hr., ALP activity test was performed. To evaluate effect of cycloheximide in ALP activity, 96-well plate was added to saponin and cycloheximide. In control group, the plate was added saponin only. The results were as follows. 1. After the various concentration of total saponin was added in the medium, 500 and $1000{\mu}g/ml$ of total saponin showed cytotoxic effect of ROS(P<0.005). 2. In contrast to control group, 7.6, 15.6, 31.25, 62.5 and $250{\mu}g/ml$ of total saponin increased ALP activity significantly. 3. Otherwise, 500 and $1000{\mu}g/ml$ of total saponin decreased ALP activity significantly(P<0.005). 4. As the time span increases, $31.25{\mu}g/ml$ of total saponin increased ALP activity. 5. Cycloheximide decreased saponin-indueced ALP actitity in ROS(P<0.005). These results suggest that Ginseng total saponin stimulates the ALP activity of rat osteoblastic cells.

• Journal of agriculture & life science
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• v.44 no.4
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• pp.45-55
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• 2010

In this study, the acetylcholinesterase (AChE) inhibition and neuronal cell protective effects of water, 100% methanol and dichlromethane extracts from garlic were investigated. We found that dichloromethane extract of garlic resulted in a dose-dependent manner on AChE inhibition ($IC_{50}$: $36.1{\mu}g/mL$). In cell viability assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT), cell viabilities of water, 100% methanol and dichlromethane extracts were lower (almost under 40%) than amyloid ${\beta}$ protein ($A{\beta}$)-induced neurotoxicity. Because $A{\beta}$ is also known to increase neuronal cell membrane breakdown, neuronal apoptosis was further confirmed by lactate dehydrogenase (LDH) and neutral red uptake (NRU) assay. Water extract presented relative protection against $A{\beta}$-induced membrane damage in LDH assay. However all garlic extracts showed significant problem with decrease of cell viability in NRU assay, especially at dichloromethan extract. To determine active compounds in column fractions (98:2 fraction) from dichloromethane extract which showed significant AChE inhibitory effect, we performed HPLC and LC-MS analysis. It was supposed that garlic may contain allyl methyl disulfide, diallyl monosulfide, and diallyl disulfide as active compounds.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.2
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• pp.213-220
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• 2016

Mast cells are primary mediators of allergic inflammation. Beta-1,3-glucan (BG) protects against infection and shock by activating immune cells. Activation of the BG receptor induces an increase in intracellular $Ca^{2+}$, which may induce exocytosis. However, little is known about the precise mechanisms underlying BG activation of immune cells and the possible role of mitochondria in this process. The present study examined whether BG induced mast cell degranulation, and evaluated the role of calcium transients during mast cell activation. Our investigation focused on the role of the mitochondrial calcium uniporter (MCU) in BG-induced degranulation. Black mouse (C57) bone marrow-derived mast cells were stimulated with $0.5{\mu}g/ml$ BG, $100{\mu}g/ml$ peptidoglycan (PGN), or $10{\mu}M$ A23187 (calcium ionophore), and dynamic changes in cytosolic and mitochondrial calcium and membrane potential were monitored. BG-induced mast cell degranulation occurred in a time-dependent manner, and was significantly reduced under calcium-free conditions. Ruthenium red, a mitochondrial $Ca^{2+}$ uniporter blocker, significantly reduced mast cell degranulation induced by BG, PGN, and A23187. These results suggest that the mitochondrial $Ca^{2+}$ uniporter has an important regulatory role in BG-induced mast cell degranulation.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.7143-7147
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• 2015

Gold nanoparticles (GNPs) were conjugated with gallic acid (GA) at various concentrations between 30 and $150{\mu}M$ and characterized using transmission electron microscopy (TEM) and UV-Vis spectroscopy (UV-VIS). The anticancer activities of the gallic acid-stabilized gold nanoparticles against well-differentiated (M213) and moderately differentiated (M214) adenocarcinomas were then determined using a neutral red assay. The GA mechanism of action was evaluated using Fourier transform infrared (FTIR) microspectroscopy. Distinctive features of the FTIR spectra between the control and GA-treated cells were confirmed by principal component analysis (PCA). The surface plasmon resonance spectra of the GNPs had a maximum absorption at 520 nm, whereas GNPs-GA shifted the maximum absorption values. In an in vitro study, the complexed GNPs-GA had an increased ability to inhibit the proliferation of cancer cells that was statistically significant (P<0.0001) in both M213 and M214 cells compared to GA alone, indicating that the anticancer activity of GA can be improved by conjugation with GNPs. Moreover, PCA revealed that exposure of the tested cells to GA resulted in significant changes in their cell membrane lipids and fatty acids, which may enhance the efficacy of this anticancer activity regarding apoptosis pathways.

• Molecules and Cells
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• v.23 no.3
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• pp.363-369
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• 2007

Mitochondria play a central role in energy-generating processes and may be involved in the regulation of channels and receptors. Here we investigated TRPM7, an ion channel and functional kinase, and its regulation by mitochondria. Proton ionophores such as CCCP elicited a rapid decrease in outward TRPM7 whole-cell currents but a slight increase in inward currents with pipette solutions containing no MgATP. With pipette solutions containing 3 mM MgATP, however, CCCP increased both outward and inward TRPM7 currents. This effect was reproducible and fully reversible, and repeated application of CCCP yielded similar decreases in current amplitude. Oligomycin, an inhibitor of $F_1/F_O$-ATP synthase, inhibited outward whole-cell currents but did not affect inward currents. The respiratory chain complex I inhibitor, rotenone, and complex III inhibitor, antimycin A, were without effect as were kaempferol, an activator of the mitochondrial $Ca^{2+}$ uniporter, and ruthenium red, an inhibitor of the mitochondrial $Ca^{2+}$ uniporter. These results suggest that the inner membrane potential (as regulated by proton ionophores) and the $F_1/F_O$-ATP synthase of mitochondria are important in regulating TRPM7 channels.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.313-318
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• 2004

Di-2-ethylhexyl phthalate (DEHP) is a widely used plasticizer known to be a suspected xenoestrogen and a causative agent of oxidative damage to the RBC cell membrane ir vitro. We evaluated the toxic effects of a scarcely documented aquatic environmental pollutant, DEHP, on selected haematological endpoints in the bagrid catfish, Pseudobagrus fulvidraco. Bagrid catfish were exposed to DEHP (300, 1,000 mg DEHP kg body weight$^{-1}$) through thrice intraperitoneal injection and effects were assessed in blood of the exposed organisms. Haematological property, serum organic and inorganic chemistry were monitored in blood of Bagrid catfish. DEHP exposed-fish showed erythropenia; low hematocrit (Ht) and hemoglobin (Hb) content and red blood cell count showed a significantly higher than in that of the control group. The treatment group showed a significantly lower concentration of serum total protein, cholesterol and triglyceride compared with those in the control group. The value of calcium and osmolality were significantly decreased in the DEHP treatment group, compared with the control group.

• Toxicological Research
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• v.35 no.1
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• pp.13-24
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• 2019

Numerous ethnomedicinal uses have been attributed to different parts of Annona senegalensis (ASE), including its uses as food and food additives. The present study investigated toxicological and antioxidant effects of 28 days administration of ethanol extracts of ASE stem bark to Wistar strain albino rats. Acute toxicity test was done to determine lethal dose in Wistar rats while sub-acute toxicity test was conducted on rats divided into four groups (A - control, B - 50 mg/kg, C - 100 mg/kg, D - 150 mg/kg, respectively and treated for 28 days. Oxidative stress markers in liver and kidney as well as hepatic succinate dehydrogenase activity in the mitochondrial and post mitochondrial fractions (PMF) were evaluated. The $LD_{50}$ value of ASE was > 2,000 mg/kg. White blood cell counts gradually increased, but red blood cell counts and haematocrits level decreased significantly (p < 0.05) by about 50%. Liver enzymes in the serum and mitochondrial succinate dehydrogenase activity increased significantly (p < 0.05). Superoxide dismutase and catalase activities also increased in liver mitochondria and PMF while malondialdehyde (MDA) and reduced glutathione levels increased only in the PMF. Furthermore, only MDA levels increased significantly in the kidney after 28 days extract administration. Histopathological examination showed hepatic necrosis and no obvious signs of nephrotoxicity. Anona senegalensis is relatively safe, but prolonged ingestion could induce oxidative stress and impair ATP synthesis through the modulation of the activity of mitochondrial succinate dehydrogenase.