• The Journal of Korean Physical Therapy
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• 제19권5호
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• pp.65-76
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• 2007

Purpose: It is generally accepted that smooth muscle contraction is triggered by intracellular $Ca^{2+}$ ($[Ca^{2+}]_i$) released from intracellular $Ca^{2+}$ stores such as sarcoplasmic teticulum (SR) and from the extracellular space. The increased $[Ca^{2+}]^i$ can phosphorylate the 20,000 dalton myosin light chain $(MLC_{20})$ by activating MLC kinase (MLCK), and this initiates smooth muscle contraction. In addition to the $[Ca^{2+}]_i$MACK-tension pathway, a number of intracellular signal molecules, including mitogen-activated protein kinase (MAPK), protein kinase C (PKC) and others, play important roles in the regulation of smooth muscle contraction. However, the mechanisms regulating contraction of depletion of SR $Ca^{2+}$ in mouse gastric smooth muscle strips is not still clear. Methods: To investigate the rotes of $Ca^{2+}$ influx and SR $Ca^{2+}$ release channel on gastric motility, isometric contraction and $[Ca^{2+}]_i$ were examined in mouse gastric smooth muscle strips. Results: High KCl, ryanodine, an activator of $Ca^{2+-}$induced $Ca^{2+}$ release channel, and cyclopiazonic acid (CPA), an inhibitor of SR $Ca^{2+-}$ATPase evoked a sustained increase in muscle contraction and $[Ca^{2+}]_i$. These increases induced by high KCl, ryanodine, and CPA were partially blocked by application of verapamil ($10{\mu}M$), a L-type $Ca^{2+}$ channel inhibitor. Additionally, in $Ca^{2+-}$free solution (1 mM EGTA), ryanodine and CPA had no effect contraction and $[Ca^{2+}]_i$ in fundic muscle strips. Conclusion: These results that extracellular $Ca^{2+}$ influx and depletion of SR trigger $Ca^{2+}$ influx through verapamil-sensitive $Ca^{2+}$ channel, and extracellular and SR $Ca^{2+}$ store may functionally involve in the subcellular $Ca^{2+}$ mobilization in mouse gastric muscle.

• 대한약리학회지
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• 제32권1호
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• pp.57-66
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• 1996

파충류 골격근의 근소포체에서 칼슘유리 채널의 존재를 밝히고저 뱀 골격근에서 근소포체를 분리하여 SDS-PAGE 전기영동, RyR의 정제, $[^3H]ryanodine$ 결합실험 및 $^{45}Ca$ 유리 실험으로 아래와 같은 결과를 얻었다. 1) 뱀골격근 소포체도 단일 band의 high molecular weight 단백을 가지고 있고, 그 mobility는 포유류 골격근의 것과 유사했다. 2) RyR의 정제과정에서 얻어진 $[^3H]ryanodine$의 peak 결합 분획에서 high molecular weight의 단백분획이 발견되었다. 3) 뱀 골격근 SR vesicles에 대한 $[^3H]ryanodine$의 maximum binding site와 Kd값은 각각 6.36 pmole/mg protein과 17.62nM이었으며, $[^3H]ryanodine$의 특이성 결합은 칼슘과 AMP에 의해 유의성있게 증가되었고 (P<0.005), tetracaine에 의해 억제되지 않았으나 ruthenium red와 $MgCl_2$에 의해 일부만 억제되었다. 4) 근 소포체로부터 $^{45}Ca$ 유리는 낮은 농도의 칼슘 $(1{\sim}10{\mu}M)$과 AMP에 의해 증가되었고 (P<0.05), 고농도의 칼슘 $(300{\mu}M)$, tetracaine, ruthenium red 또는 $MgCl_2$에 의해 억제되었다 (P<0.05). 이상의 실험성적으로 파충류 (뱀)의 골격근에도 칼슘유리 채별이 있어 근 수축시 세포내 칼슘 농도 조절에 관여할 수 있을 것으로 여겨지며, 채널의 기능적 특징 일부가 포유류의 것과 유사한 것으로 사료된다.

• 대한약리학회지
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• 제29권2호
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• pp.195-202
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• 1993

스트렙토조토신으로 당뇨를 유발시킨 쥐의 심근 근장그물에서 칼슘이동이 저하됨을 볼 수 있었다. 칼슘이동의 저하는 최대칼슘 uptake의 감소와 칼슘에 대한 affinity의 감소로 나타났다. 이러한 심근 근장그물의 기능저하가 나타나는 작용기전이 심근 근장그물 단백의 산화성 손상과 관계가 있는지를 살펴보았다. 당뇨쥐에서는 glycohemoglobin과 carbonyl group의 양이 현저히 증가됨을 볼 수 있었다. 한편으로 cyclic AMP 의존성 protein kinase의 catalytic subunit에 의한 phospholamban 인산화에 의해 심근 근장고물 칼슘이동의 증가를 보였고, 이 증가는 대조군에 비하여 당뇨군에서 훨씬 현저하게 나타났다. SDS-polyacrylamide를 이용한 전기영동후 autoradiogram을 통하여 확인한 phospholamban 인산화는 당뇨군에서 진한 band로 나타남이 확인되었다. 이상의 결과로 미루어 당뇨군의 심근 근장그물 기능저하는, 기초상태에서 아마도 심근내 저하된 norephinephrine 양으로 인하여 phospholamban 인산화 정도가 적으므로 근장그물 $Ca^{2+}-ATPase$ 억제가 나타남을 제시해 주며, 근장그물 단백의 산화성 손상도 당뇨성 심근질한을 일으킬 수 있는 또 다른 요인 중의 하나로 생각된다.

• Journal of Microbiology
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• 제35권3호
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• pp.200-205
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• 1997

Bothl $Ca^{2+}$ and Sr$^{2+}$-containing methanol dehydrogenases (MDH) were purified to homogeneity with yields of 48% and 42%, respectively, from Methylabacillus methanolovorus sp. strain SK5. Most of the biochemical and structural properties were similar to each other. However, some differences were found: (1) although the overall shape of the absorption spectrum of Sr$^{2+}$-MDH was very similar to that of $Ca^{2+}$-MDH, the absorption intensity originating from the cofactor in Sr$^{2+}$. MDH was higher than that in $Ca^{2+}$-MDH. Small blue shift of the maximum was also observed. These are probably due to a difference in redox state of the cofactors in $Ca^{2+}$ and Sr$^{2+}$-MDH; (2) Sr$^{2+}$-MDH was more heat-stable than $Ca^{2+}$-MDH above 56$^{\circ}C$; (3) the V$_{max}$ values for the methanol-dependent activities of Sr$^{2+}$- and $Ca^{2+}$-MDH in the presence of 3 mM KCN were 2.038 and 808 nmol/mg protein/min, respectively. In addition, the $K_{m}$ values of Sr$^{2+}$ and $Ca^{2+}$ MDH for methanol were 12 and 21 $\mu$M, respectively; (4) the endogenous activity of $Ca^{2+}$-MDH was more sensitive than that of Sr$^{2+}$-MDH in the presence of cyanide; (5) Diethyl pyrocarbonate treatment increased the enzyme activities of $Ca^{2+}$- and Sr$^{2+}$-MDH 4.2- and 1.4-folds, respectively. These results indicate that Sr$^{2+}$ stabilizes the structural conformation and enhances the activity of MDH more than $Ca^{2+}$.

• 한국축산식품학회지
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• 제21권1호
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• pp.32-37
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• 2001

The study investigated the effects of protein concentration, EGTA and strength of hydrostatic pressure on pH, viscosity and turbidity for ultra filtrated skim milk retentates. The results showed that hydrostatic pressure treatments up to 600 MPa did not affect the viscosity of skim milk, while the turbidity of skim milk increased at higher than 200 MPa. Addition of EGTA caused reduction in turbidity of skim milk, two times (2SR) and three times (3SR) concentrated skim milk retentates. Viscosity for 2SR and 3SR increased proportionally to the amount of EGTA, but viscosity of skim milk was not influenced by EGTA. High pressure treatment also did not cause any difference in viscosity and turbidity of skim milk. However, this treatment decreased viscosity and turbidity for 2SR and 3SR. In particular, 200 MPa treatment showed to induce a higher decrease in turbidity compared with 400 MPa.

• Genomics & Informatics
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• 제11권1호
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• pp.15-23
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• 2013

CD8+T cells are key factors mediating hepatitis B virus (HBV) clearance. However, these cells are killed through HBV-induced apoptosis during the antigen-presenting period in HBV-induced chronic liver disease (CLD) patients. Interferon-inducible protein 6 (IFI6) delays type I interferon-induced apoptosis in cells. We hypothesized that single nucleotide polymorphisms (SNPs) in the IFI6 could affect the chronicity of CLD. The present study included a discovery stage, in which 195 CLD patients, including chronic hepatitis B (HEP) and cirrhosis patients and 107 spontaneous recovery (SR) controls, were analyzed. The genotype distributions of rs2808426 (C > T) and rs10902662 (C > T) were significantly different between the SR and HEP groups (odds ratio [OR], 6.60; 95% confidence interval [CI], 1.64 to 26.52, p = 0.008 for both SNPs) and between the SR and CLD groups (OR, 4.38; 95% CI, 1.25 to 15.26; p = 0.021 and OR, 4.12; 95% CI, 1.18 to 14.44; p = 0.027, respectively). The distribution of diplotypes that contained these SNPs was significantly different between the SR and HEP groups (OR, 6.58; 95% CI, 1.63 to 25.59; p = 0.008 and OR, 0.15; 95% CI, 0.04 to 0.61; p = 0.008, respectively) and between the SR and CLD groups (OR, 4.38; 95% CI, 1.25 to 15.26; p = 0.021 and OR, 4.12; 95% CI, 1.18 to 14.44; p = 0.027, respectively). We were unable to replicate the association shown by secondary enrolled samples. A large-scale validation study should be performed to confirm the association between IFI6 and HBV clearance.

• Macromolecular Research
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• 제14권2호
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• pp.140-145
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• 2006

E-science refers to the large-scale science that will increasingly be carried out through distributed global collaborations enabled by the Internet. The Grid is a service-oriented architecture proposed to provide access to very large data collections, very large scale computing resources and remote facilities. Web services, which are server applications, enable online access to service providers. Web portal interfaces can further hide the complexity of accessing facility's services. The main use of synchrotron radiation (SR) facilities by protein crystallographers is to collect the best possible diffraction data for reasonably well defined problems. Significant effort is therefore being made throughout the world to automate SR protein crystallography facilities so scientists can achieve high throughput, even if they are not expert in all the techniques. By applying the above technologies, the e-HTPX project, a distributed computing infrastructure, was designed to help scientists remotely plan, initiate and monitor experiments for protein crystallographic structure determination. A description of both the hardware and control software is given together in this paper.

• Biomolecules & Therapeutics
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• 제30권5호
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• pp.409-417
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• 2022

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide, and accumulating evidence indicates that mitochondrial dysfunction is associated with progressive deterioration in PD patients. Previous studies have shown that sinapic acid has a neuroprotective effect, but its mechanisms of action remain unclear. The neuroprotective effect of sinapic acid was assayed in a PD mouse model generated by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as well as in SH-SY5Y cells. Target protein expression was detected by western blotting. Sinapic acid treatment attenuated the behavioral defects and loss of dopaminergic neurons in the PD models. Sinapic acid also improved mitochondrial function in the PD models. MPTP treatment increased the abundance of mitochondrial fission proteins such as dynamin-related protein 1 (Drp1) and phospho-Drp1 Ser616. In addition, MPTP decreased the expression of the REV-ERB α protein. These changes were attenuated by sinapic acid treatment. We used the pharmacological REV-ERB α inhibitor SR8278 to confirmation of protective effect of sinapic acid. Treatment of SR8278 with sinapic acid reversed the protein expression of phospho-Drp1 Ser616 and REV-ERB α on MPTP-treated mice. Our findings demonstrated that sinapic acid protects against MPTP-induced PD and these effects might be related to the inhibiting abnormal mitochondrial fission through REV-ERB α.

• BMB Reports
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• 제46권5호
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• pp.237-243
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• 2013

Heart failure is one of the leading causes of sudden death in developed countries. While current therapies are mostly aimed at mitigating associated symptoms, novel therapies targeting the subcellular mechanisms underlying heart failure are emerging. Failing hearts are characterized by reduced contractile properties caused by impaired $Ca^{2+}$ cycling between the sarcoplasm and sarcoplasmic reticulum (SR). Sarcoplasmic/endoplasmic reticulum $Ca^{2+}$ ATPase 2a (SERCA2a) mediates $Ca^{2+}$ reuptake into the SR in cardiomyocytes. Of note, the expression level and/or activity of SERCA2a, translating to the quantity of SR $Ca^{2+}$ uptake, are significantly reduced in failing hearts. Normalization of the SERCA2a expression level by gene delivery has been shown to restore hampered cardiac functions and ameliorate associated symptoms in pre-clinical as well as clinical studies. SERCA2a activity can be regulated at multiple levels of a signaling cascade comprised of phospholamban, protein phosphatase 1, inhibitor-1, and $PKC{\alpha}$. SERCA2 activity is also regulated by post-translational modifications including SUMOylation and acetylation. In this review, we will highlight the molecular mechanisms underlying the regulation of SERCA2a activity and the potential therapeutic modalities for the treatment of heart failure.

• Molecules and Cells
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• 제26권3호
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• pp.265-269
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• 2008

Calumenin, a multiple EF-hand $Ca^{2+}$ binding protein is located in the SR of mammalian heart, but the functional role of the protein in the heart is unknown. In the present study, an adenovirus gene transfer system was employed for neonatal rat heart to examine the effects of calumenin over-expression (Calu-OE) on $Ca^{2+}$ transients. Calu-OE (8 folds) did not alter the expression levels of DHPR, RyR2, NCX, SERCA2, CSQ and PLN. However, Calu-OE affected several parameters of $Ca^{2+}$ transients. Among them, prolongation of time to 50% baseline ($T_{50}$) was the most outstanding change in electrically-evoked $Ca^{2+}$ transients. The higher $T_{50}$ was due to an inhibition of SERCA2-mediated $Ca^{2+}$ uptake into SR, as tested by oxalate-supported $Ca^{2+}$ uptake. Furthermore, co-IP study showed a direct interaction between calumenin and SERCA2. Taken together, calumenin in the cardiac SR may play an important role in the regulation of $Ca^{2+}$ uptake during the EC coupling process.