• Molecules and Cells
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• v.20 no.2
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• pp.247-255
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• 2005

Three different catalase cDNA clones (CaCat1, CaCat2, and CaCat3) were isolated from hot pepper (Capsicum annuum L.), and their expression patterns were analyzed at the levels of mRNA and enzyme activity. Northern hybridization showed that the three catalase genes were differentially expressed in various organs, and that expression of CaCat1 and CaCat2 was regulated differently by the circadian rhythm. In situ hybridization revealed different spatial distributions of CaCat1 and CaCat2 transcripts in leaf and stem. In response to wounding and paraquat treatment, CaCat1 mRNA increased at 4-12 h in both paraquat-treated and systemic leaves. In contrast, wounding had no significant effect on expression of the catalase genes. The increase of catalase activity in the paraquat-treated and systemic leaves paralleled that of CaCat1 mRNA, but did not match that of CaCat1 mRNA in paraquat-treated stems. Our results suggest that CaCat1 may play a role in responses to environmental stresses.

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.337-340
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• 1999

Luminescence of bismuth activated CaS, CaS:Bi, prepared in sodium polysulfide is studied. Excitation spectrum of CaS:Bi shows a band at 350 nm due to the recombination process between holes in Na+Ca2+ and electrons in conduction bands, in addition to bands at 260 nm from band gap of CaS, and at 320 nm (1S0→1P1) and at 420 nm (1S0→3P1) from electronic energy transitions of Bi. Emission band at 450 nm is from 3P1→1S0 transition of Bi3+, bands at 500 nm and 580 nm correspond to recombinations of electron donors (Bi3+Ca2+ and VS2-) with acceptors (VCa2+ and Na+Ca2+). Emission band of 3P1→1S0 transition is shifted to longer wavelength from CaS:Bi to BaS:Bi, due to the increase of the Stokes shift by the decrease of the crystal field parameter from CaS:Bi to BaS:Bi.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.783-796
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• 1997

The relaxation induced by stimulation of the inhibitory non-adrenergic, non-cholinergic (iNANC) nerve is mediated by the release of iNANC neurotransmitters such as nitric oxide (NO), vasoactive intestinal peptide (VIP) and adenosine triphosphate (ATP). The mechanisms of NO, VIP or ATP-induced relaxation have been partly determined in previous studies, but the detailed mechanism remains unknown. We tried to identify the nature of iNANC neurotransmitters in the smooth muscle of guinea pig ileum and to determine the mechanism of the inhibitory effect of nitric oxide. We measured the effect of NO-donors VIP and ATP on the intracellular $Ca^{2+}$ concentration$([Ca^{2+}]_i)$, by means of a fluorescence dye(fura 2) and tension simultaneously in the isolated guinea pig ileal smooth muscle. Following are the results obtained. 1. Sodium nitroprusside $(SNP:10^{-5}\;M)$ or S -nitro-N-acetyl-penicillamine $(SNP:10^{-5}\;M)$ decreased resting $[Ca^{2+}]_i$ I and tension of muscle. SNP or SNAP also inhibited rhythmic oscillation of $[Ca^{2+}]_i$ and tension. In 40mM $K^+$ solution or carbachol ($(CCh:10^{-6}\;M)$-induced precontracted muscle, SNP decreased muscle tension. VIP did not change $[Ca^{2+}]_i$ and tension in the resting or precontracted muscle, but ATP increased resting $[Ca^{2+}]_i$ and tension in the resting muscle. 2. 1H-[1,2,4]oxadiazol(4,3-a)quinoxalin-1-one $(ODQ:1\;{\mu}M)$, a specific inhibitor of soluble guanylate cyclase, limited the inhibitory effect of SNP 3. Glibenclamide $(10\;{\mu}M)$, a blocker of $K_{ATP}$ channel, and 4-aminopyridine (4-AP:5 mM), a blocker of delayed rectifier K channel, apamin $(0.1\;{\mu}M)$, a blocker of small conductance $K_{Ca}$ channel had no effect on the inhibitory effect of SNP. Iberiotoxin $(0.1\;{\mu}M)$, a blocker of large conductance $K_{Ca}$ channel, significantly increased the resting $[Ca^{2+}]_i$, and tension, and limited the inhibitory effect of SNP. 4. Nifedipine $(1\;{\mu}M)$ or elimination of external $Ca^{2+}$ decreased not only resting $[Ca^{2+}]_i$ and tension but also oscillation of $[Ca^{2+}]_i$ and tension. Ryanodine $(5\;{\mu}M)$ and cyclopiazonic acid $(10\;{\mu}M)$ decreased oscillation of $[Ca^{2+}]_i$ and tension. 5. SNP decreased $Ca^{2+}$ sensitivity of contractile protein. In conclusion, these results suggest that 1) NO is an inhibitory neurotransmitter in the guinea pig ileum, 2) the inhibitory effect of SNP on the $[Ca^{2+}]_i$ and tension of the muscle is due to a decrease in $[Ca^{2+}]_i$ by activation of the large conductance $K_{Ca}$ channel and a decrease in the sensitivity of contractile elements to $Ca^{2+}$ through activation of G-kinase.

• Journal of Embryo Transfer
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• v.11 no.3
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• pp.259-269
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• 1996

The present study was undertaken to examine the critical effect of $Ca^2$+ concentration on electrostimulation and post-electrostimulation media for electric activation of in vitro matured oocytes of Korean Native Cattle. Oocytes collected from slaughterhouse ovaries were matured in TCM 199 containing FSH, estradiol-17$\beta$ and FBS with granulosa cell monolayer for 24 hours and denuded with hyaluronidase. And then cumulus-free oocytes were submitted to a DC field of 1.0 kV/cm for 60 $\mu$sec in electroporation media(0.28 M mannito' and PBS) with different $Ca^2$+ concentations (0.00, 0.05, 0.10 and 0.15 mM). Stimulated oocytes were stained and examined for pronuclear formation after incuhation in SOF for 12 hours. The rates of pronuclear formation in hovine oocytes electrically stimulated in 0.28 M mannitol with 0.05, 0.10 and 0.15 mM $Ca^2$+(60.3, 82.2 and 75.0%) were significantly higher than without $Ca^2$+(6.3%) at 12 hours after an electric pulse(p<0.005). The activation rates of Korean Native Cattle oocytes stimulated in PBS supplemented with 0.05, 0.10 and 0.15 mM $Ca^2$+(71.0, 75.8 and 75.4%) were significantly higher than without $Ca^2$+(23.5%) after post-stimulation incubation(p<0.005). After incubation of oocytes in SOF with and without $Ca^2$+ following electric stimulation in 0.28 M mannitol with 0.10 mM $Ca^2$+, the rates of pronuclear formation of bovine oocytes in $Ca^2$+-free SOF(85.7%) was significantly higher than in SOF with 1.71 mM $Ca^2$+(62.5%, p<0.05). When oocytes were stimulated in two electrostimulation media supplemented with $Ca^2$+ and incubated in $Ca^2$+-free SOF, there were no significant differences in the rates of pronuclear formation hetween 0.28 M mannitol and PBS. These results indicate that a single electric pulse could induce activation of Korea Native Cattle oocytes in 0.28 M mannitol and PBS supplemented with $Ca^2$+. Furthermore, to improve the activation rates, it was hetter that stimulated oocytes were incubated in $Ca^2$+-free SOF after electric stimulation than in SOF with $Ca^2$+.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.1
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• pp.53-59
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• 2011

The secretion of insulin from pancreatic ${\beta}$-cells is triggered by the influx of $Ca^{2+}$ through voltage-dependent $Ca^{2+}$ channels. The resulting elevation of intracellular calcium ($[Ca^{2+}]_i$) triggers additional $Ca^{2+}$ release from internal stores. Less well understood are the mechanisms involved in $Ca^{2+}$ mobilization from internal stores after activation of $Ca^{2+}$ influx. The mobilization process is known as calcium-induced calcium release (CICR). In this study, our goal was to investigate the existence of and the role of caffeine-sensitive ryanodine receptors (RyRs) in a rat pancreatic ${\beta}$-cell line, INS-1 cells. To measure cytosolic and stored $Ca^{2+}$, respectively, cultured INS-1 cells were loaded with fura-2/AM or furaptra/AM. $[Ca^{2+}]_i$ was repetitively increased by caffeine stimulation in normal $Ca^{2+}$ buffer. However, peak $[Ca^{2+}]_i$ was only observed after the first caffeine stimulation in $Ca^{2+}$ free buffer and this increase was markedly blocked by ruthenium red, a RyR blocker. KCl-induced elevations in $[Ca^{2+}]_i$ were reduced by pretreatment with ruthenium red, as well as by depletion of internal $Ca^{2+}$ stores using cyclopiazonic acid (CPA) or caffeine. Caffeine-induced $Ca^{2+}$ mobilization ceased after the internal stores were depleted by carbamylcholine (CCh) or CPA. In permeabilized INS-1 cells,$Ca^{2+}$ release from internal stores was activated by caffeine, $Ca^{2+}$, or ryanodine. Furthermore, ruthenium red completely blocked the CICR response in perrneabilized cells. RyRs were widely distributed throughout the intracellular compartment of INS-1 cells. These results suggest that caffeine-sensitive RyRs exist and modulate the CICR response from internal stores in INS-1 pancreatic ${\beta}$-cells.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.223-230
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• 1999

Alterations of cardiovascular function associated with various thyroid states have been studied. In hyperthyroidism left ventricular contractility and relaxation velocity were increased, whereas these parameters were decreased in hypothyroidism. The mechanisms for these changes have been suggested to include alterations in the expression and/or activity levels of various proteins; ${\alpha}-myosin$ heavy chain, ${\beta}-myosin$ heavy chain, ${\beta}-receptors,$ the guanine nucleotide-binding regulatory protein, and the sarcolemmal $Ca^{2+}-ATPase.$ All these cellular alterations may be associated with changes in the intracellular $Ca^{2+}$ concentration. The most important regulator of intracellular $Ca^{2+}$ concentration is the sarcoplasmic reticulum (SR), which serves as a $Ca^{2+}$ sink during relaxation and as a $Ca^{2+}$ source during contraction. The $Ca^{2+}-ATPase$ and phospholamban are the most important proteins in the SR membrane for muscle relaxation. The dephosphorylated phospholamban inhibits the SR $Ca^{2+}-ATPase$ through a direct interaction, and phosphorylation of phospholamban relieves the inhibition. In the present study, quantitative changes of $Ca^{2+}-ATPase$ and phospholamban expression and the functional consequences of these changes in various thyroid states were investigated. The effects of thyroid hormones on (1) SR $Ca^{2+}$ uptake, (2) phosphorylation levels of phospholamban, (3) SR $Ca^{2+}-ATPase$ and phospholamban protein levels, (4) phospholamban mRNA levels were examined. Our findings indicate that hyperthyroidism is associated with increases in $Ca^{2+}-ATPase$ and decreases in phospholamban levels whereas opposite changes in these proteins occur in hypothyroidism.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.91-102
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• 1990

The effects of extracellular $Ca^{2+}$ and various $Ca^{2+}$ antagonists on endothelium-dependent relaxation to acetylcholine were studied in the isolated rabbit thoracic aorta in order to elucidate the control mechanism of endothelium derived relaxing factor (EDRF) release. Endothelium was removed from aortic strips by gentle rubbing with cotton ball. The effect of hemoglobin on basal tension was also observed with hemolysate. The results obtained were as follows: 1) Endothelium-dependent relaxation (EDR) to acetylcholine (ACh) showed biphasic pattern; the initial rapid relaxation phase and the late slow relaxation phase. 2) With the depletion of the extracellular $Ca^{2+}$, EDR was gradually suppressed, especially the late slow relaxation. 3) Verapamil, nifedipine, $Mn^{2+}$ and $Cd^{2+}$ had not any effect on EDR, while $La^{3+}$ and $Co^{2+}$ suppressed EDR completely. 4) The resting tension of the strips with rubbed endothelium was not altered by the addition of hemoglobin. That of the strips with intact endothelium, however, was enhanced and EDR to ACh was completely blocked From these results, we suggest that extracellular $Ca^{2+}$ is necessary for ACh-induced slow relaxation while $Ca^{2+}$ antagonists have not any effect on EDR.

• Analytical Science and Technology
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• v.25 no.5
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• pp.333-338
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• 2012

IQ motif-containing GTPase-activating proteins (IQGAPs), which are well-known $Ca^{2+}$-independent calmodulin (CaM) binding proteins, are involved in various cellular functions such as cell proliferation, carcinogenesis and cell migration. The IQGAP3 similar to IQGAP1 has four repeated IQ motifs, which are crucial for CaM binding. It has been recently shown that all four IQ motifs of the IQGAP1 could bind to CaM, while not clear the binding of four IQ motifs of the IQGAP3. In this study, we examined the binding between CaM and each IQ motif of IQGAP3. As a result, we found that IQ2 and IQ3, but not IQ1 and IQ4, have a $Ca^{2+}$-independent CaM binding activity. We also found that IQ(3.5-4.4) on the IQGAP3 has $Ca^{2+}$-dependent CaM binding activity as similar with that of IQGAP1. This finding indicates that IQ motifs of the IQGAP3 plays a dynamic role via different interaction of IQ motifs with $Ca^{2+}$/CaM or apoCaM.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.182-189
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• 1996

It has been known that spermatozoa should obtain their fertilizing ability through capacitation and acrosome reaction, and that in these processes of fertilization, Ca2+ platys an important role for their conjugation. Therefore the present study has been designed in order to clarify the effect of fluctuation of the media Ca2+ level and the intracellular concentration of the spermatozoa on the acrosomes. During the incubation of spermatozoa, a considerable fluctuation in the media Ca2+ level has been observed after the BSA administration and the media concentration of Ca2+. It is deduced that these fluctuation rates may have an effect on the acrosome reaction. The fluctuation of K+ flux has been observed in accordance with the incubation period over time, and it's concentration seems to be closely related with the acrosomal reaction. The respiratory exchange rate (RERI of the spermatozoa is kept more regular in the BSA and Cacl2 administration groups than the non-administration group. Based on the experimental findings, it is possible to deduce a hypothesis from these findings that physiological activities of the acrosome reaction are not functionally related to the media Ca2+ level and the intracellular influx of Ca2+ concentration, although Ca2+ platys an important role as a stimulating factor in the acrosome reaction.

• Journal of Ginseng Research
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• v.30 no.2
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• pp.57-63
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• 2006

One of the various signaling agents in the animal cells is the simple ion called calcium, $Ca^{2+}$.$Ca^{2+}$ controls almost everything that animals do, including fertilization, secretion, metabolism, muscle contractions, heartbeat, learning, memory stores, and more. To do all of this, $Ca^{2+}$ acts as an intracellular messenger, relaying information within cells to regulate their activity. In contrast, the maintenance of intracellular high $Ca^{2+}$ concentrations caused by various excitatory agents or toxins can lead to the disintegration of cells (necrosis) through the activity of $Ca^{2+}$-sensitive protein-digesting enzymes. High concentrations of calcium have also been implicated in the more orderly programs of cell death known as apoptosis. Because this simple ion, acts as an agent for cell birth, life and death, to coordinate all of these functions, $Ca^{2+}$ signalings should be regulated precisely and tightly. Recent reports have shown that ginsenosides regulate directly and indirectly intracellular $Ca^{2+}$ level with differential manners between neuronal and non-neuronal cells. This brief review will attempt to survey how ginsenosides differentially regulate intracellular $Ca^{2+}$ signaling mediated by various ion channels and receptor activations in neuronal and non-neuronal cells.