• The Korean Journal of Physiology and Pharmacology
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• 제17권3호
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• pp.223-228
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• 2013

The calcium-activated $K^+$ ($BK_{Ca}$) channel is one of the potassium-selective ion channels that are present in the nervous and vascular systems. $Ca^{2+}$ is the main regulator of $BK_{Ca}$ channel activation. The $BK_{Ca}$ channel contains two high affinity $Ca^{2+}$ binding sites, namely, regulators of $K^+$ conductance, RCK1 and the $Ca^{2+}$ bowl. Lysophosphatidic acid (LPA, 1-radyl-2-hydroxy-sn-glycero-3-phosphate) is one of the neurolipids. LPA affects diverse cellular functions on many cell types through G protein-coupled LPA receptor subtypes. The activation of LPA receptors induces transient elevation of intracellular $Ca^{2+}$ levels through diverse G proteins such as $G{\alpha}_{q/11}$, $G{\alpha}_i$, $G{\alpha}_{12/13}$, and $G{\alpha}s$ and the related signal transduction pathway. In the present study, we examined LPA effects on $BK_{Ca}$ channel activity expressed in Xenopus oocytes, which are known to endogenously express the LPA receptor. Treatment with LPA induced a large outward current in a reversible and concentration-dependent manner. However, repeated treatment with LPA induced a rapid desensitization, and the LPA receptor antagonist Ki16425 blocked LPA action. LPA-mediated $BK_{Ca}$ channel activation was also attenuated by the PLC inhibitor U-73122, $IP_3$ inhibitor 2-APB, $Ca^{2+}$ chelator BAPTA, or PKC inhibitor calphostin. In addition, mutations in RCK1 and RCK2 also attenuated LPA-mediated $BK_{Ca}$ channel activation. The present study indicates that LPA-mediated activation of the $BK_{Ca}$ channel is achieved through the PLC, $IP_3$, $Ca^{2+}$, and PKC pathway and that LPA-mediated activation of the $BK_{Ca}$ channel could be one of the biological effects of LPA in the nervous and vascular systems.

• 한국미생물·생명공학회지
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• 제33권4호
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• pp.315-318
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• 2005

The effects of inorganic salts and feather concentrations on pretense production by Bacillus megaterium F7-1 were investigated. Pretense production was dependent on the presence of phosphates in the medium. Supplementation of medium with calcium ion slightly increased protease production. The highest protease production was obtained at $1.4\%$ feather. The optimal medium contained $2.0\%$ glucose, $0.8\%$ skim milk, $0.06\%\;K_{2}HPO_{4}\%,\;0.04\%\;KH_{2}PO{4},\;0.06\%\;NaCl,\;0.03\%\;MgCl_{2}\cdot6H_{2}O,\;0.002\%\;CaCl_{2}\cdot2H_{2}O,\;and\;1.4\%$ whole feather. By using this optimized medium, increased production of the protease was achieved compared with the cases of using basal medium.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.263-263
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• 1994

Annexin I is a member of the in family of calcium dependent phospholipid banding proteins and is an in vitro phospholipase $A_2$ (PLA$_2$) inhibitor. The mechanism of PLA$_2$ inhibition by annexin I is still ambiguous. The structure of annexin I was studied at the atomic level by using nuclear magnetic resonance (NMR), circular dichrotsm (CD) and fluorescence spectroscopy. Recombinant human annexin I and N-terminally truncated annexin I (1-31 deleted: d-annexin I) were purified and their NMR spectra were compared. The NMR spectra of the two were similar. When $Ca^{2+}$ ion added to annexin I ad d-annexin I, peak broadening occurred, but no significant spectroscopic change was observed. When porcine pancreatic PLA$_2$ was added to deuterium labeled annexin I, an interaction of annexin I with PLA$_2$ was observed as indicated by the disappearance and shift of several peaks in the NMR spectrum. This result supports a protein-protein interaction mechanism for PLA$_2$ inhibition by annexin I.I.

• Animal cells and systems
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• 제14권4호
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• pp.245-252
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• 2010

Iron uptake in mitochondria and fractionated mitochondria compartments was studied to understand iron transport in heart mitochondria. The inner membrane is most active in iron uptake. Mitochondrial uptake was dependent on iron concentration and the amount of mitochondria. Iron transport was inversely proportional to pH in the range of 6.0 to 8.0. Iron transport reached a maximum after 30 min of incubation at $37^{\circ}C$. Iron uptake was inhibited by 1 mM ATP and stimulated by 1 mM ADP. The oxidative phosphorylation inhibitor oligomycin inhibited iron uptake, but rotenone and antimycin A did not. The divalent ions $Mg^{2+}$, $Cu^{2+}$, $Mn^{2+}$, and $Zn^{2+}$ suppressed iron uptake at $10\;{\mu}M$ and stimulated it at 1 mM. The divalent ion $Ca^{2+}$ stimulated iron uptake at $10\;{\mu}M$ and suppressed it at 1 mM, competing with iron. The uptake of calcium was stimulated by 10 to $1000\;{\mu}M$ ATP, while iron uptake was stimulated reciprocally by 10 to $1000\;{\mu}M$ ADP, suggesting that these ions have movements similar to those of ATP and ADP.

• 대한본초학회지
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• 제36권5호
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• pp.15-27
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• 2021

Objectives : The processing of Pinelliae Tuber and Arisaematis Rhizoma is a crucial step to reduce the severe acrid irritation mainly due to the needle-like crystals (raphides). Ginger, alum and bile juice have been used as adjuvant materials for the processing. Methods : Bibliographic research on ancient processing and experimental processing was performed to investigate the toxicity reduction mechanisms of the processing with ginger, alum and bile juice. Results : Ginger has been a major adjuvant for the processing of Pinelliae Tuber, followed by alum and bile juice since Song (宋) and Myeong (明) dynasties, and Arisaematis Rhizoma has been mainly used as Damnamseong (膽南星). The raphides consisting of calcium oxalate, lectin, agglutinin and polysaccharides can induce acrid irritation and the inflammatory reactions. The lipophilic components in the ginger denatured the structure of raphides and 6-gingerol-contained ginger extract attenuated the inflammatory reaction. The calcium ion (Ca²⁺) of calcium oxalate was substituted to the aluminium ion (Al³⁺) of the alum, which damaged the calcium oxalate structure. Lectin attached to the surface of raphides was dissolved in alum solution and consequently its structure was denatured. The cholate in the bile juice formed the complex with the oxalate anion or the calcium cation. Moreover, the enzymes activated by Lactobacillus or Bifidobacterium during the fermentation promoted the fragmentation of oxalate. Conclusion : The adjuvant materials damaged the raphides by denaturing or degrading the calcium oxalate, resulting in the reduction of acrid irritation. Further experimental studies would support the toxicity reduction mechanism of the processing.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.627-636
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• 2022

In nuclear power plants and other nuclear facilities the removal of cobalt from radioactive liquid waste is needed to reduce the radioactivity concentration in effluents. In liquid wastes containing strong organic complexing agents such as EDTA cobalt removal can be problematic due to the high stability of the Co-EDTA complex. In this study, the removal of cobalt from NaNO₃ solutions using antimony oxide (Sb₂O₃) synthesized from potassium hexahydroxoantimonate was investigated in the absence and presence of EDTA. The uptake studies on the ion exchange material were conducted both in the dark (absence of UV-light) and under UV-C irradiation. Ca²⁺ or Ni²⁺ were included in the experiments as competing cations to test the selectivity of the ion exchanger. Results show that UV-C irradiation noticeably enhances the cobalt sorption efficiency on the antimony oxide. It was shown that nickel decreased the sorption of cobalt to a higher extent than calcium. Finally, the sorption data collected for Co²⁺ on antimony oxide was modeled using six different isotherm models. The Sips model was found to be the most suitable model to describe the sorption process. The Dubinin-Radushkevich model was further used to calculate the adsorption energy, which was found to be 6.2 kJ mol^-1.

• 청정기술
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• 제24권1호
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• pp.41-49
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• 2018

$25^{\circ}C$에서 $CO_2$ 흡착을 위한 작업용량과 $CO_2/CO$ 선택계수를 현저하게 향상시키기 위하여 서로 다른 전하와 이온반경을 갖는 $Na^+$, $N^+$, $Ca^{2+}$와 $Cu^{2+}$로 이온교환된 Y 제올라이트들이 연구되었다. 매우 소량인 0.012% $Ca^{2+}$로 이온교환된 NaY는 7회의 반복적인 $CO_2$ 흡착/탈착 싸이클 동안에도 완전히 가역적이었으므로 기존에 보고된 것들과는 달리 표면에 카보네이트는 생성되지 않는 것으로 생각된다. 4 bar 이상에서 2.00% CaY, 1.60% CuY와 1.87% LiY 모두 NaY와 매우 유사한 $CO_2$ 흡착성능을 보였다할지라도 그보다 낮은 압력에서는 이들의 흡착능은 감소하였고 그 정도는 금속이온들의 종류에 의존하였다. 0.5 ~ 2.5 bar에서 $CO_2$ 흡착성능은 NaY > 1.60% CuY > 2.00% CaY > 1.87% LiY의 순으로 나타났는데, 이들 모두 동일한 faujasite 골격과 약 2.6의 Si/Al 비율을 가지므로 골격, 골격조성, 유효세공크기와 채널구조에 있어서 차이는 없기 때문에 약한 루이스산의 특성을 갖는 $CO_2$의 구별되는 흡착거동은 이온교환에 따른 국부염기도와 흡착 포텐셜 에너지의 변화 때문일 것이다. $CO_2$ 흡착과는 다른 경향성이 CO 흡착에서 나타났고 이는 보다 약한 사극자 상호작용 때문이다. 0.012 ~ 5.23% Ca 함량을 갖는 Y 제올라이트에 $CO_2$와 CO 흡착 시 Ca 함량에 따른 현저한 의존성이 존재하였는데 0.05% 이하에서 $CO_2$ 흡착능은 증가한 반면에 그 이상에서는 감소하였다. 이러한 경향에도 불구하고 Ca 함량의 증가와 함께 작업용량과 $CO_2/CO$ 선택계수는 현저히 증가하였고, 5.23% CaY의 경우 작업용량은 $2.37mmol\;g^{-1}$, 선택계수는 4.37이었는데 본 연구에서 얻어진 작업용량은 문헌에 보고된 벤치마크와 유사한 수준이었다.

• 청정기술
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• 제28권4호
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• pp.269-277
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• 2022

생물학적 효소 반응 산업의 발전으로 인해 바이오매스 자원으로부터 젖산을 대량 생산하는 것이 가능해짐에 따라 젖산의 추가적인 탈수 반응을 통해 고흡수성 수지 SAP, 디스플레이의 점접착제 등의 원료가 되는 아크릴산을 생산하는 친환경 공정이 많은 주목을 받고 있다. 본 연구에서는 젖산 탈수 반응에서 높은 활성을 가지나, 비활성화가 빠른 단점을 가지는 NaY 제올라이트 촉매의 산점 및 염기점을 조절하여, 높은 아크릴산 선택도를 장시간 유지 가능한 촉매를 개발하고자 하였다. 첫번째로 NaY 모촉매에 부분적으로 칼슘을 치환하여 산/염기도를 변화시키고자 하였으며, 이온 교환법과 초기습식 함침법을 모두 적용하여 그 효과를 탐색하였다. 그 결과 직접적으로 Ca를 함침하는 것이 선택도 및 안정성 측면에서 우수한 것을 확인하였으며, 16시간 반응 동안 40% 수율의 AA를 안정적으로 생산하였다. 산/염기 특성 분석 결과, 함침된 Ca는 주로 CaO 형태로 촉매 외피에 존재하면서, 젖산 탈수 반응을 위한 추가적인 염기점으로 작용하는 것으로 나타났다. 추가적으로 NaY 모촉매의 산세기를 약화시키면서 기공 내외적으로 Ca을 고르게 분산시키기 위해, KOH 처리를 통한 탈규소화 후, Ca를 함침하였다. 그러나 기존 Ca-NaY 촉매 대비 아크릴산 선택도가 증진되는 효과는 관찰하지 못하였다. 최종적으로 KOH 처리 촉매에서 Ca 담지양을 1 wt%에서 5 wt%로 증가시켜 염기점 양을 증진시켜 보았다. 그 결과, 기존 1 wt% Ca가 함침된 촉매에 비해 아크릴산 선택도를 65%까지 증진시킬 수 있었으며, 24시간 반응 동안 촉매 안정성 또한 꾸준하게 유지되어, 젖산 탈수 반응에서 염기점 조절이 선택도 및 안정성 향상에 중요한 변수임을 제시하였다.

• 생약학회지
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• 제45권3호
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• pp.214-219
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• 2014

Artemisia apiacea is a traditional herbal medicine using treatment of eczema and jaundice in Eastern Asia including China, Korea, and Japan. In this study, the three phytosterol constituents were isolated and identified from the hexane fraction of 80% aqueous methanol extract of A. apiacea. Compounds were isolated using open column chromatography (silica gel). Their chemical structures were also established using $^1H$-NMR and $^{13}C$-NMR. Moreover, neuroprotective activity of each compound against glutamate-induced neurotoxicity in hippocampal HT-22 cell line was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore, Inhibition of reactive oxygen species (ROS) and calcium ion ($Ca^{2+}$) accumulation were measured for elucidation of neuroprotective mechanism of isolated compounds. They showed that stigmasterol had neuroprotective activity against the glutamate-induced toxicity by inhibition of ROS and $Ca^{2+}$ production. In conclusion, isolated compound of A. apiacea might be useful for therapeutic agent against neurodegenerative diseases.

• Journal of Plant Biology
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• 제39권4호
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• pp.295-300
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• 1996

The physiological effects of oligogalacturonic acid (OGA:D. P. 6-7), a product of acid hydrolysis of polygalacturonic acid (PGA), on ethylene biosynthesis in mung bean (Vigna radiata W.) hypocotyl segments was studied. Among PGA, OGA and monogalacturomic acid (MGA), only OGA stimulated ethylene production in mung bean hypocotyl segments, and the most effective concentraton of OGA was 50$\mu\textrm{g}$/mL. Time course data indicated that this stimulatiion effect of OGA appeared after 90 min incubation period and continued until 24 h. When indol-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) were treated with OGA to investigate the mechanism of OGA on ethylene production, they did not show synergistic effects on ethylene production. The stimulation of ethylene production by OGA was due to the increase of in vivo ACC synthase activity, but OGA treatment had no effect of in vivo ACC oxidase activity. The effect of aminoethoxy vinyl glycine (AVG) and Co2+, the inhibitor of ethylene synthesis, was siminished a little by the OGA, but the treatment of Ca2+, known to increase ACC, with OGA did not increase the ethylene production, this effect seems to be specific for Ca2+ because other divalent cation, Mg2+, did not show the inhibition of OGA-indyuced ethylene production. It is possible that the OGA adopts a different signal transduction pathway to the ethylene bioxynthesis.