• The Journal of Natural Sciences
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• v.18 no.1
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• pp.55-63
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• 2007

This research was conducted to investigate the effects of calcium solution spray on the accumulation of calcium into apple fruit. $^{45}_{CaCl_2}$ applied to fruit with different growth stages showed that more $^{45}Ca$ was penetrated into fruits when applied in the late stage than early stage. Slight radioactivity was detected only in pedicel except leaf when $^{45}Ca$ was treated on the leaves proximate to the fruit. When the Ca was treated on fruit surface only, calcium contents of fruit was increased.

• The Journal of Natural Sciences
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• v.6 no.1
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• pp.49-54
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• 1993

This study was conducted to investigate the influence of various calcium salts on the accumulation of calcium in apple fruits when sprayed on whole tree. Differences in the total calcium contents of fruits were found between calcium sources and cultivars. In 'Tsugaru' , calcium nitrate, calcium chloride, and calcium carbonate were all effective but only calcium chloride and calcium carbonate appeared to be effective in 'Fuji' . Major parts of the applied calcium were accumulated in the feel and outer flesh. Ethylene evolution of fruit was retarded during storage with the increase of total calcium content in 'Fuji' fruit treated calcium acetate.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.787-794
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• 2010

Calcium plays a role as a signaling molecule in various cellular events. It has been reported that calcium suppresses adipocyte differentiation only in the early phase of adipogenesis. Herein, we demonstrate that treatment of A23187, a mobilizer of intracellular calcium, on day 4 post adipocyte differentiation could still reduce lipid accumulation in differentiating 3T3-L1 cells for 48 h. In addition, luciferase reporter gene and RT-Q-PCR assays demonstrate that A23187 can selectively inhibit transcriptional activities and expression of PPAR$\gamma$ and LXR$\alpha$, suggesting that A23187 may reduce lipid accumulation in the late phase of adipogenesis via downregulation of PPAR$\gamma$ and LXR$\alpha$ expression and transactivation. Moreover, inhibition of HDAC activity by trichostatin A (TSA) partially blocked A23187-mediated downregulation of transcriptional activities of PPAR$\gamma$ and LXR$\alpha$. Together, our data demonstrate that calcium mobilization inhibits expression and transcriptional activities of PPAR$\gamma$ and LXR$\alpha$, resulting in reduced lipid accumulation in differentiating adipocytes, and thus, mobilization of intracellular calcium in adipocytes may serve as a new preventive and therapeutic approach for obesity.

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.132-136
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• 1996

Exogenously applied oxygen free radical generating agent, pyrogallol, highly elevated extracellular glutamate accumulation and augmented N-methyl-D-aspartate (NMDA)-induced glutamate accumulation in cerebellar granule neuronal cells, but did not in astrocytes. Superoxide dismutase remarkably decreased the pyrogallol-induced glutamate accumulation, but either NMDA or kainate antagonists did not. In addition, pyrogallol did not affect the NMDAinduced intracellular calcium elevation. Pyrogallol partially blocked glutamate uptake into astrocytes. These results suggest that oxygen free radicals elevate extracellular glutamate accumulation by stimulating the release of glutamate as well as blocking the glutamate uptake.

• Korean Journal of Plant Resources
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• v.27 no.4
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• pp.344-353
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• 2014

This study was carried out to analyze the effect of arsenic types on growth and arsenic accumulation ability of Pteris multifida. Among arsenic pollution sources, Sodium arsenate, Calcium arsenate, Sodium arsenite and Potassium arsenite were treated in horticultural compost contaminated with $500mg{\cdot}kg^{-1}$. P. multifida was cultivated for 12 weeks. The results of study, Calcium arsenate treatment showed slightly decreased growth of P. multifida. But, growth of P. multifida cultivated in the remaining arsenic treatment was similar to untreated control plot. With only short-term cultivation of 4 weeks, aerial part of P. multifida in Sodium arsenate treatment showed high arsenic accumulation of $2,289.5mg{\cdot}kg^{-1}DW$. The arsenic accumulation ($2,956.0mg{\cdot}kg^{-1}DW$) was the highest at 12 week. On the other hand, underground part showed the highest arsenic accumulation in Potassium arsenite treatment ($2,470.2mg{\cdot}kg^{-1}DW$) and Calcium arsenate treatment accumulated $1,060.7mg{\cdot}kg^{-1}DW$ of arsenic. Regardless of arsenic types, aerial part of P. multifida was absorbed more than $1000mg{\cdot}kg^{-1}DW$ of arsenic. And removal of arsenic in soil was also higher. Therefore, Pteris multida is considered to be suitable phytoremediation meterial of various arsenic contaminated areas.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.97-99
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• 1996

Intracellular gradients of the free calcium concentration are thought to be critical for the localization of functional responses within a cell. The mechanism of mechanotransduction may be associated with the localized accumulation of calcium stores for shear stress-exposed endothelial cells. The distribution of the calcium stores and the formation of the stress fibers were investigated by the indirect double immunofluorescent staining method with the calreticulin antibody and rhodamine phalloidin under flow condition. The shear stress of steady flow reorganized the cytoskeleton structure including the bundling and translocation to focal contacts. The calcium stores translocated from the cytoplasm to the focal contacting area. Consequently. accumulation of the calcium stores may participate in the shear stress-induced cytoskeleton organization of endothelial cells.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.259-264
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• 2004

The present study describes the ameliorating effect of $Ca^{++}\;on\;Cd^{++}$ toxicity on the germination, early growth of mungbean seedlings, nitrogen assimilation enzyme. s-nitrate reductase (NR), nitrite reductase (NIR), anti-oxidant enzymes (POD, CAT and SOD) and on the accumulation of hydrogen peroxide and sulphydryls. $Cd^{++}$ inhibited seed germination and root and shoot length of seedlings. While NR activity was down- regulated, the activities of NIR, POD and SOD were up- regulated with $Cd^{++}$ treatment. $Cd^{++}$ treatment also increased the accumulation of sulphydryls and peroxides, which is reflective of increased thiol rich proteins and oxidative stress. $Ca^{++}$ reversed the toxic effects of $Cd^{++}$ on germination and on early growth of seedlings as well as on the enzyme activities, which were in turn differentially inhibited with a combined treatment with calcium specific chelator EGTA. The results indicate that the external application of $Ca^{++}$ may increase the tolerance capacity of plants to environmental pollutants by both up and down regulating metabolic activities. Abbreviations: $Cd^{++}= cadmium,\;Ca^{++} = calcium$, NR= nitrate reductase, NIR=nitrite reductase, POD = peroxidse, SOD= superoxide dismutase, CAT= catalase, EGTA= ethylene glycol-bis( $\beta-aminoethyl ether$)-N,N,N,N-tetraacetic acid.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.7-12
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• 1997

Glutamate uptake inhibitor, L-trans-pyrrolidine-2, 4-dicarboxylate (PDC, $20{\mu}M$) elevated basal and N-methyl-D-aspartate (NMDA, $100{\mu}M$)-induced extracellular glutamate accumulation, while it did not augment kainate $100{\mu}M$-induced glutamate accumulation in cultured cerebellar granule neurons. However, pretreatment with PDC for 1 h significantly reduced NMDA-induced glutamate accumulation, but did not affect kainate-induced response. Pretreatment with glutamate $(5{\mu}M)$ for 1 h also reduced NMDA-induced glutamate accumulation, but did not kainate-induced response. Upon a brief application (3-10 min), PDC did neither induce elevation of intracellular calcium concentration $([Ca^{2+}]_i)$ nor modulate NMDA-indLiced $[Ca^{2+}]_1$ elevation. Pretreatment with PDC for 1 h reduced NMDA-induced $[Ca^{2+}]_1$ elevation, but it did not reduce kainate-induced $[Ca^{2+}]_1$ elevation. These results suggest that glutamate concentration in synaptic clefts of neurana cells is increased by prolonged exposure (1 h) of the cells to PDC, and the accumulated glutamate subsequently induces selective desensitization of NMDA receptor.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.24-29
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• 1998

Effect of extracellular calcium in vitellogenin (VTG) production in response to estradiol-17 $\beta$ $(E_2,\;2\times10^{-6}M)$ was examined in primary hepatocyte culture of rainbow trout, Onchorhynchus mykiss. Total calcium in estrogenized sera significantly increased, compared with the control, while diffusible calcium was insignificant. However, diffusible calcium in the incubation medium with $E_2$ was significantly reduced, compared with the control. The uptake of extracellular calcium by cultured hepatocytes signifIcantly increased 90 min after $E_2$ addition. Moreover, the accumulation of intracellular calcium increased in the cultures with $E_2$, regardless of the calcium concentrations in the incubation media. In addition, $E_2-primed $ VTG production was significantly decreased by withdrawal of E_2$ from the incubation medium. Moreover, VTG production by $E_2-primed$ hepatocytes was reduced by removing calcium from the incubation medium with or without $E_2$. These results suggest that the entry of extracellular calcium into the cytoplasm is an important step for VTG production in primary hepatocyte cultures in rainbow trout.

• YAKHAK HOEJI
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• v.35 no.1
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• pp.45-60
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• 1991

lonophores, uniquely, create specific pathways of ion permeability in model and cell membranes. Calcium-transporting ionophores of microbiological origin, such as A23187 and ionomycin, have been used as experimental tools to elucidate the physiological role of calcium as a second messenger in many cell types. These ionophores are believed to bypass the initial ligand-receptor step in the activation of cells by increasing membrane permeability to calcium. In this report, we shall discuss several naturally occurring substances that share some properties of calcium-ionophores, primarily concentrating on oxidized fatty acids. We have previously demonstrated that oxidized linoteic and arachidonic acids, obtained either by lipoxygenase catalysis or nonenzymatic processes, significantly promote calcium translocation in a two-phase partition model and modulate calcium-transporting function in the isolated sarcoplasmic reticulum vesicles obtained from mammalian hearts. We have also confirmed that calcium-ionophoric properties are due not to their general amphiphilic nature of certain lipids, but to distinct structural characteristics. Although there are some skeptical views on the occurrence of ionophores in higher organisms, increasing evidence suggests that membrane lipids or their derivatives may serve as physiological calcium-ionophores. Abnormal accumulation of lipid peroxidation products(particularly end products), however, may be associated with the general oxidative damages as seen in many pathological conditions.