• BMB Reports
• /
• v.32 no.6
• /
• pp.561-566
• /
• 1999

CA(1-8)-ME(1-12) [CA-ME], composed of cecropin A(1-8) and melittin(1-12), is a synthetic antimicrobial peptide having potent antibacterial and antitumor activities with minimal hemolytic activity. In order to investigate the effects of the flexible hinge sequence, Gly-Ile-Gly, of CA-ME on antibiotic activity, CA-ME and three analogues, CA-ME1, CA-ME2, and CA-ME3, were synthesized. The Gly-Ile-Gly sequence of Ca-ME was deleted in CA-ME1 and replaced with Pro and Gly-Pro-Gly in CA-ME2 and CA-ME3, respectively. CA-ME1 and CA-ME3 showed a significant decrease in antitumor activity and phospholipid vesicle-disrupting ability. However, CA-ME2 showed similar antitumor and vesicle-disrupting activities, as compared with CA-ME. These results suggest that the flexibility or ${\beta}$-turn induced by Gly-Ile-Gly or Pro in the central part of CA-ME may be important in the electrostatic interaction of the N-terminus cationic ${\alpha}$-helical region with the cell membrane surface and the hydrophobic interaction of the C-terminus amphipathic ${\alpha}$-helical region with the hydrophobic acyl chains in the cell membrane. CA-ME3 exhibited lower antitumor and vesicle-disrupting activities than CA-ME and CA-ME2. This result suggests that the excessive ${\beta}$-turn structure caused by the Gly-Pro-Gly sequence in CA-ME3 seems to interrupt ion channel/pore formation in the lipid bilayer. We concluded that the appropriate flexibility or bilayer. We concluded that the appropriate flexibility or ${\beta}$-turn structure provided by the central hinge is responsible for the effective antibiotic activity of the antimicrobial peptides with the helix-hinge-helix structure.

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

• Archives of Pharmacal Research
• /
• v.28 no.4
• /
• pp.413-420
• /
• 2005

We previously demonstrated the ability of ginseng saponins (active ingredients of Panax ginseng) to enhance $Ca^{2+}$-activated $Cl^{-}$ current. The mechanism for this ginseng saponin-induced enhancement was proposed to be the release of $Ca^{2+}$ from $IP_{3}-sensitive$ intracellular stores through the activation of PTX-insensitive $G\alpha_{q/11}$ proteins and PLC pathway. Recent studies have shown that calmodulin (CaM) regulates $IP_{3}$ receptor-mediated $Ca^{2+}$ release in both $Ca^{2+}-dependent$ and -independent manner. In the present study, we have investigated the effects of CaM on ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current responses in Xenopus oocytes. Intraoocyte injection of CaM inhibited ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement, whereas co-injection of calmidazolium, a CaM antagonist, with CaM blocked CaM action. The inhibitory effect of CaM on ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement was dose- and time-dependent, with an $IC_{50} of 14.9\pm3.5 {\mu}M$. The inhibitory effect of CaM on saponin's activity was maximal after 6 h of intraoocyte injection of CaM, and after 48 h the activity of saponin recovered to control level. The half-recovery time was calculated to be $16.7\pm4.3 h$. Intraoocyte injection of CaM inhibited $Ca^{2+}$-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement and also attenuated $IP_{3}$-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement. $Ca^{2+}$/CaM kinase II inhibitor did not inhibit CaM-caused attenuation of ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement. These results suggest that CaM regulates ginseng saponin effect on $Ca^{2+}$-activated $Cl^{-}$ current enhancement via $Ca^{2+}$-independent manner.

• Biomolecules & Therapeutics
• /
• v.15 no.4
• /
• pp.212-217
• /
• 2007

In atrial myocytes, lacking t-tubules, $Ca^{2+}$ current ($I_{Ca}$)-initiated $Ca^{2+}$ release at the peripheral junctional sites propagates into the interior of the cell by diffusion of $Ca^{2+}$. We have previously reported that time of activation of the central sites is independent of $I_{Ca}$. In the present study we have probed the effects of Bay K 8644 on $Ca^{2+}$ propagation wave to the center of the myocyte using rapid 2-D confocal $Ca^{2+}$ imaging in the rat atrial myocytes. Enhancement of $I_{Ca}$ by Bay K 8644 accelerated the rate of peripheral $Ca^{2+}$ release, but did not affect the speed of propagation of central release. In contrast, enhancement of $I_{Ca}$ by intracellular cAMP reduced the magnitude of peripheral and central $Ca^{2+}$ transients, but significantly accelerated the speed of central $Ca^{2+}$ release. Our data suggest that the speed of central $Ca^{2+}$ propagation triggered by $I_{Ca}$ is not regulated by the magnitude of either $I_{Ca}$ or local cytosolic $Ca^{2+}$ releases.

• Journal of the Korean Society for Heat Treatment
• /
• v.25 no.4
• /
• pp.175-180
• /
• 2012

Role of Ca in grain growth behavior has been investigated in hot-rolled Al-3%Mg and Al-3%Mg-0.5%Ca wrought alloys. When annealed for 1 hr from 723 to 823 K, grain size of the Al-3%Mg alloy increased rapidly above 723 K, whereas grains were relatively stable up to 773 K for the Ca-containing alloy. Grain homogeneity of the Ca-containing alloy was better than that of the Ca-free alloy both in hot-rolled and annealed states. Calculated activation energies for grain growth were 77.6 and 85.9 kJ/mole in the range of 723 to 823 K for the alloys with 0 and 0.5%Ca, respectively. Taking SEM images and EDS results into account, enhanced thermal stability in response to Ca addition would be associated with Al4Ca compounds located along the grain boundaries, which eventually play a role in restricting grain growth at elevated temperatures.

• The Korean Journal of Physiology and Pharmacology
• /
• v.11 no.5
• /
• pp.215-219
• /
• 2007

Small and large conductance $Ca^{2+}$-activated $K^+(SK_{Ca}\;and\;BK_{Ca})$ channels are implicated in the modulation of neuronal excitability. We investigated how changes in peripheral $K_{Ca}$ channel activity affect mechanical sensitivity as well as the afferent fiber type responsible for $K_{Ca}$ channel-induced mechanical sensitivity. Blockade of $SK_{Ca}$ and $BK_{Ca}$ channels induced a sustained decrease of mechanical threshold which was significantly attenuated by topical application of capsaicin onto afferent fiber and intraplantar injection of 1-ethyl-2-benzimidazolinone. NS1619 selectively attenuated the decrease of mechanical threshold induced by charybdotoxin, but not by apamin. Spontaneous flinching and paw thickness were not significantly different after $K_{Ca}$ channel blockade. These results suggest that mechanical sensitivity can be modulated by $K_{Ca}$ channels on capsaicin-sensitive afferent fibers.

• Korean Journal of Soil Science and Fertilizer
• /
• v.32 no.4
• /
• pp.333-343
• /
• 1999

To investigate the relationship between the translocation and distribution the monovalent K and Na and the divalent Sr and Ca, the natrophile and calcitrophic plant sugar beet (Beta vulgaris L.) was used. Strontium uptake and distribution are concentration and growth stage dependent. The highest Ca content occurred in the treatment of 4 : 1 mM ratio of Ca to Sr, while the highest Sr content in old leaves in the presence of 1 mM Ca and 4 mM Sr. The addition of low concentration of Sr stimulates Ca-uptake. Reversely. Sr-uptake is highest in the presence of 1 mM Ca. This result may be an antagonistic effect between Ca and Sr. The ratios of Mg to Ca and Sr are satisfactorily presented by the regression analysis. The sum of Sr and Ca contents are most significant linear to the ratio of Mg to one, showing a negative correlation. This result implies that the absorption of Mg and Ca or Sr is antagonistic. In the presence of only 5 mM Sr, K and Na-uptakes increases, while Sr in the presence of Ca does not affect the change in the K and Na assimilation and their ratios. The ratios of K to Na is also not changed. A little addition of Sr could more effectively retain the chlorophyll loss while only in the presence of Sr, the chlorophyll levels are considerably reduced.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.11
• /
• pp.6241-6243
• /
• 2013

Objective: To explore the predictive value of tumor markers, including cancer antigen 72-4 (CA72-4), cancer antigen 15-3 (CA15-3) and cancer antigen 125 (CA125), in single or combined detection, for the diagnosis of ovarian cancer. Methods: 120 patients diagnosed with ovarian cancer from August 2011 to March 2013 and 80 patients diagnosed with benign ovarian tumors were enrolled in this test, along with 50 health examination women randomly selected from the database as controls. Serum levels of CA72-4, CA15-3 and CA125 in this study were determined by electrochemiluminescence (ECL). Results: Serum levels of CA72-4, CA15-3 and CA125 in ovarian cancer were higher than those in healthy group and benign group (P<0.01).The sensitivity of combined detection of those three tumor markers for diagnosis of ovarian cancer was obviously higher than with single detection with each marker (P<0.01). Conclusions: CA72-4, CA15-3 and CA125 could be a good combination in the diagnosis of ovarian cancer. Patients whose tumor markers continue to increase should be highly suspected of malignancy.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1071-1074
• /
• 2006

Ca/Ag double layer which is fabricated by thermal evaporation exists as the double layer of (Ca+O)/(Ag+Ca). In Ca layer, are crystalline Ca(OH)2 and amorphous Ca and in Ag layer, are crystalline Ag and amorphous Ca. And for the certain thickness of Ag, in the Ca/Ag double layer, the thicker Ca is, the higher transmittance is.

• Biomedical Science Letters
• /
• v.4 no.1
• /
• pp.27-33
• /
• 1998

This study has been designed in order to examine a physiological role of $Ca^{2+}$ which has been known as an essential factor for capacitation, to confirm whether the enzyme activity of $Ca^{2+}$-ATPase on capacitation is important or not, and to clarify relationship between various levels of the $Ca^{2+}$ concentration and $Ca^{2+}$-ATPase which has been known to be an important factor of the plasma membranes. In the present study applying quercetin, a $Ca^{2+}$-ATPase inhibitor, the enzymatic effect of $Ca^{2+}$-ATPase on capacitation was found to be remarkable: a significant increase of the transition from the original type (type A) to the type B and the type AR of the spermatozoa. This finding suggests that $Ca^{2+}$-ATPase plays an important role in the efflux and the influx of the $Ca^{2+}$ which has been known to be an essential factor the capacitation and acrosome reaction, and that the inhibitory action of the $Ca^{2+}$-ATPase might be a prerequsite step toward the acrosome reaction. The conclusion reached can be deduced as follows: increment of the intracelluar $Ca^{2+}$ concentration occurred by controlling the slope of $Ca^{2+}$ concentration through $Ca^{2+}$-ATPase activities in both the intra- and extracelluar fluid may be an important procedure for capacitation and acrosome reaction, and ultimately for fertilization of the spermatozoa and the ova.