• BMB Reports
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• v.34 no.3
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• pp.212-218
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• 2001

Although the blockage of a cell cycle by specific inhibitors of $Ca^{2+}/$calmodulin-dependent protein kinase II (CaMK-II) is well known, the activity profile of CaMK-II during the cell cycle in the absence of any direct effectors of the enzyme is unclear. The activity of native CaMK-II in NIH 3T3 cells was examined by the use of cell cycle-specific arresting and synchronizing methods. The total catalytic activity of CaMK-II in arrested cells was decreased about 30% in the M phase, whereas the $Ca^{2+}$-independent autonomous activity increased about 1.5-fold in the M phase and decreased about 50% at the G1/S transition. The in vivo phosphorylation level of CaMK-II was lowest at G1/S and highest in M. The CaMK-II protein level was unchanged during the cell cycle. When the cells were synchronized, the autonomous activity was increased only in M. These results indicate that the physiologically relevant portion of CaMK-II is activated only in M, and that the net activation of CaMK-II is required in mitosis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.1
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• pp.32-37
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• 2002

Ca$^{2+}$ plays an important the in firmness retention of plant tissues. In this study, effect of CaCl$_2$on extention of shelf-life of kakdugi, and its effective conditions of addition were determined. The rates of pH decrease, acidity increase and mechanical texture decrease during fermentation wire reduced by the addition of CaCl$_2$. Furthermore, sensory characteristics of kakdugi such as crispness, sourness and overall taste were improved. Addition of 0.1% CaCl$_2$in brine solution and 0.05% CaCl$_2$to seasoning was the most effective condition to extend shelf-life of kakdug.g.

• The Korean Journal of Pharmacology
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• v.27 no.2
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• pp.167-181
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• 1991

The present study was an attempt to investigate the effect of forskolin on secretion of catecholamines (CA) evoked by Ach, excess $K^+$, DMPP, McN-A-343 and caffeine from the isolated perfused rat adrenal glands and to elucidate its mechanism of action. The perfusion with forskolin (1.0 uM) for 1 min into the adrenal vein enhanced markedly the secreation of CA evoked by Ach (50 ug), excess $K^+$ (56 mM) DMPP (100 uM) and by caffeine (0.3 mM) but did not that by McN-A-343. Forskolin alone did not potentiate the CA secretion. Moreover, forskolin augmented the CA release evoked by the above same stimulation even in the absence of extracellular calcium. The 1 min perfusion of 300 uM-dibutyryl cyclic AMP (DBcAMP), which is known to increase cyclic AMP levels, led to enhancement of Ca secretion evoked by Ach, excess $K^+$ and DMPP but did not that by McN-A-343 and caffeine. DBcAMP by itself also did not augment the CA secretion. In the calcium-free medium DBcAMP significantly enhanced the CA secretion by the same stimulation, except for the case of McN-A-343. These experimental results suggest that forskolin activates adenylate cyclase, resulting the elevation of cyclic AMP which may potentiate cholinergic nicotinic receptor-mediated and also depolarization-dependent CA secretion and that it may alter the intracellular calcium homeostasis in the rat adrenal glands.

• Journal of Nutrition and Health
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• v.21 no.3
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• pp.173-181
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• 1988

Various types of evidence suggest that some changes in cellular in cellular calcium may well signal the initiation of a chain of events leading to the physiological effects of the bone resorbing agents. The effects of 1,25-dihydorxycholecalciferol, $1.25\textrm{(OH)}_2\textrm{D}_3$, Ca ionophore A23187 and calcium antagonist, diltiazem on bone resprption and the cellular transport of Ca were investigated. Bone $^{45}\textrm{Ca}$ desaturation experiment was realized in isolated heterogenous rat bone cells after equilibrating the cells with $^{45}\textrm{Ca}$. Results of $^{45}\textrm{Ca}$ desaturation experiments were analysed by fitting the $^{45}\textrm{Ca}$ desaturation curve to a model of 2 exponential terms which indicated the presence of 2 exchangeable cellular calcium pools. $1.25\textrm{(OH)}_2\textrm{D}_3$ (0.5ng/$m\ell$) induced significantly bone resorption which was decreased by the physiological dose of diltiazeme(above 5nmol/$m\ell$) although it was ineffective alone. Ionophore A23187 (0.2$\mu\textrm{g}$/$m\ell$) decreased Ca release from bone but no additivity of effect with diltiazem(20nmol/$m\ell$) was observed. $1.25\textrm{(OH)}_2\textrm{D}_3$ (0.5ng/$10^{6}$ cells) had a moderate effect on the two kinetic phases of $^{45}\textrm{Ca}$ desaturation curve and these values were normalized when diltiazeme (20nmol/$10^{6}$ cells) was added along with $1.25\textrm{(OH)}_2\textrm{D}_3$. Ionophore($0.05\mu\textrm{g}$/$10^{6}$ cells) alone increased specifically the value of the slow turnover rate which was not affected by addition of diltiazem. The hypothesis concerning the involvement of calcium in bone resorption seems in fact to be verified in case of $1.25\textrm{(OH)}_2\textrm{D}_3$ but more unsettled for Ca inophore A23187.

• International Journal of Oral Biology
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• v.47 no.3
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• pp.33-40
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• 2022

Store-operated Ca²⁺ entry (SOCE) represents one of the major Ca²⁺ entry routes in non-excitable cells. It is involved in a variety of fundamental biological processes and the maintenance of Ca²⁺ homeostasis. The Ca²⁺ release-activated Ca²⁺ (CRAC) channel consists of stromal interaction molecule and Orai; however, the role and action of Homer proteins as an adaptor protein to SOCE-mediated Ca²⁺ signaling through the activation of CRAC channels in non-excitable cells still remain unknown. In the present study, we investigated the role of Homer2 in the process of Ca²⁺ signaling induced by the interaction between CRACs and Homer2 proteins in non-excitable cells. The response to Ca²⁺ entry by thapsigargin-mediated Ca²⁺ store depletion remarkably decreased in pancreatic acinar cells of Homer2^-/- mice, as compared to wild-type cells. It also showed critical differences in regulated patterns by the specific blockers of SOCE in pancreatic acinar cells of Homer2^-/- mice. The response to Ca²⁺ entry by the depletion in Ca²⁺ store markedly increased in the cellular overexpression of Orai1 and STIM1 as compared to the overexpression of Homer2 in cells; however, this response was remarkably inhibited by the overexpression of Orai1, STIM1, and Homer2. These results suggest that Homer2 has a critical role in the regulatory action of SOCE activity and the interactions between CRAC channels.

• BMB Reports
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• v.41 no.11
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• pp.771-777
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• 2008

Calmodulin (CaM) proteins, members of the EF-hand family of $Ca^{2+}$-binding proteins, represent important relays in plant calcium signals. Here, OsCam1-1 was isolated by PCR amplification from the rice genome. The gene contains an ORF of 450 base pairs with a single intron at the same position found in other plant Cam genes. A promoter region with a TATA box at position-26 was predicted and fused to a gus reporter gene, and this construct was used to produce transgenic rice by Agrobacterium-mediated transformation. GUS activity was observed in all organs examined and throughout tissues in cross-sections, but activity was strongest in the vascular bundles of leaves and the vascular cylinders of roots. To examine the properties of OsCaM1-1, the encoding cDNA was expressed in Escherichia coli. The electrophoretic mobility shift when incubated with $Ca^{2+}$ indicates that recombinant OsCaM1-1 is a functional $Ca^{2+}$-binding protein. In addition, OsCaM1-1 bound the CaMKII target peptide confirming its likely functionality as a calmodulin.

• Korean Journal of Materials Research
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• v.17 no.3
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• pp.137-141
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• 2007

A series of $Ca_{1-x}Sr_{x}S:Mn$ phosphors were synthesized by solid-state reactions. The emission peaks of $Ca_{1-x}Sr_{x}S:Mn$ is blue shifted front 605 to 570 nm with increasing Sr content. Since $Ca_{1-x}Sr_{x}S:Mn$. Mn phosphors exhibit strong absorption in region of 254 nm, the emission wavelength of a fluorescent lamp, these phosphors can be used as wavelength tunable emitting phosphors from reddish orange to yellow. We investigated the optical and structural properties of $Ca_{1-x}Sr_{x}S:Mn$ phosphors.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.42-48
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• 1999

This study was executed to see the effects of Ca : K ratios in me.L$^{-1}$ -0:9, 1.5:7.5, 3:6, 4.5:4.5, 6:3 - in the nutrient solution on the photosynthesis, transpiration, growth and incidence of tipburn in butterhead ‘Omega’and Leaf ‘Grand Rapids’lettuce (Lactuca sativa. L) grown in nutrient film technique(NFT). The photosynthesis of both lettuces showed high in the Ca : K ratios of 3:6 and 4.5:4.5 regardless of species. But stomatal resistance of Grand Rapids was higher than that of Omega. The highest transpiration rate of them was shown in the Ca : K ratio of 3:6. The transpiration rate of developing leaves was lower than that of expanded leaves. It was seemed to have relation with incidence of tipbum in the developing leaves. The nutrient solution treatment without Ca developed less growth than that of other treatments, especially growth and development of apical part were inhibited, so that in the both of them incidence of tipburn appeared 100 percent. The incidence of tipburn in Omega appeared 25 percent in the Ca/K ratio of 1.5:7.5, but Grand Rapids did not show it according to the Ca/K ratio in nutrient solution. The highest growth in two species was also shown in the Ca/K ratio of 3:6 except nutrient solution without Ca. This study suggested that the unbalanced ratio of Ca/K affected Ca transport in two species because of the increase of stomatal resistance and diffusive resistance and the decrease of photosynthesis and transpiration.

• Journal of Nutrition and Health
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• v.26 no.3
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• pp.277-285
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• 1993

To investigate the effects of dietary calcium levels on the Ca metabolism in a rat model of ovariectomized osteoporosis, two studies were conducted. In Expt. I, five week-old femalc rats ovariectomized and fed a low Ca diet(0.06% Ca) for four weeks were compared with rats fed a normal (0.53% Ca) or low Ca diet under the sham-operated condition. Ovariectomized rats showed a significant increase in body weight and food intake. In rats fed the low Ca diet, a remarkable decrease was shown regardless of ovariectomy in serum Ca concentration, breaking force of bones, Ca and phopsphrus contents of bones, and apparent absorption and retention of Ca. Furthermore hte decrease of Ca contents of serum and bones in rats ovariectomized and fed the low Ca diet was similar to that in rats model of postmenopausal osteoporosis. In Expt. II, rats ovariectomized and fed on the low Ca diet for four weeks were divided into three groups, those given low Ca diet, normal Ca diet and high Ca diet(1.06%) respectively. The results indicated that supplementations of Ca at the intake level of 0.53% and 1.06% for 4 weeks tend to improve the relative Ca deficiency shown in experimental rat model of ovariectomized osteoporosis.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.3
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• pp.189-194
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• 2009

This study was designed to clarify the mechanism of the inhibitory effect of forskolin on contraction, cytosolic $Ca^{2+}$ level $([Ca^{2+}]_i)$, and $Ca^{2+}$ sensitivity in guinea pig ileum. Forskolin (0.1 nM ${\sim}$ 10 ${\mu}M$) inhibited high $K^+$ (25 mM and 40 mM)- or histamine (3 ${\mu}M$)-evoked contractions in a concentration-dependent manner. Histamine-evoked contractions were more sensitive to forskolin than high $K^+$-evoked contractions. Spontaneous changes in $[Ca^{2+}]_i$ and contractions were inhibited by forskolin (1 ${\mu}M$) without changing the resting $[Ca^{2+}]_i$. Forskoln (10 ${\mu}M$ ) inhibited muscle tension more strongly than $[Ca^{2+}]_i$ stimulated by high $K^+$, and thus shifted the $[Ca^{2+}]_i$-tension relationship to the lower-right. In histamine-stimulated contractions, forskolin (1 ${\mu}M$) inhibited both $[Ca^{2+}]_i$ and muscle tension without changing the $[Ca^{2+}]_i$-tension relationship. In ${\alpha}$-toxin-permeabilized tissues, forskolin (10 ${\mu}M$) inhibited the 0.3 ${\mu}M$ $Ca^{2+}$-evoked contractions in the presence of 0.1 mM GTP, but showed no effect on the $Ca^{2+}$-tension relationship. We conclude that forskolin inhibits smooth muscle contractions by the following two mechanisms: a decrease in $Ca^{2+}$ sensitivity of contractile elements in high $K^+$-stimulated muscle and a decrease in $[Ca^{2+}]_i$ in histamine-stimulated muscle.