• 한국미생물·생명공학회지
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• 제20권3호
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• pp.257-262
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• 1992

Streptomyces virginiae가 생산하는 virginimycin 생산 유도인자(virginiae butanolide C,VB-C) 결합 단백질의 ligand(VB-C)와의 결합활성에 미치는 일반적인 성질을 검토한 결과, 본 VB-C 결합단백질은 막성분을 제외한 세포질에 90% 이상 존재하며, 최적 pH는 7.0인 것으로 입증되었다. KCL 존재하 약 15%의 결합활성이 증대되었으며,$Mo^{6+}$ 이온 존재시 60%의 결합활성 저하를 보였다.

• 대한의생명과학회지
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• 제25권4호
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• pp.302-312
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• 2019

The aim of this work was to investigate the effect of black tea extract (BTE) on collagen -induced platelet aggregation. In this study, BTE (10~500 ㎍/mL) was shown to inhibit platelet aggregation via thromboxane A₂ (TXA₂) down-regulation by blocking cyclooxygenase-1 (COX-1) activity. Also, BTE decreased intracellular Ca²⁺ mobilization ([Ca²⁺]_i). Additionally, BTE enhanced the levels of both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are aggregation-inhibiting molecules. BTE inhibited the phosphorylation of phospholipase C (PLC) γ2 and syk activated by collagen. BTE regulated platelet aggregation via cAMP-dependent phosphorylation of vasodilator-stimulated phosphoprotein (VASP) Ser¹⁵⁷. The anti-platelet effects of BTE in high fat diet (HFD)-induced obese rats were evaluated. After eight weeks of BTE treatment (300 and 600 mg/kg), the platelet aggregation rate in the treated groups was significantly less than that in the HFD-fed control group. Also, BTE exhibited a hepatoprotective effect and did not exert hepatotoxicity. Therefore, these data suggest that BTE has anti-platelet effects on collagen-stimulated platelet aggregation and may have therapeutic potential for the prevention of platelet-mediated thrombotic diseases.

• The Korean Journal of Physiology and Pharmacology
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• 제16권3호
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• pp.211-217
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• 2012

Recent studies have demonstrated that nitric oxide (NO) activates transient receptor potential vanilloid subtype 1 (TRPV1) via S-nitrosylation of the channel protein. NO also modulates various cellular functions via activation of the soluble guanylyl cyclase (sGC)/protein kinase G (PKG) pathway and the direct modification of proteins. Thus, in the present study, we investigated whether NO could indirectly modulate the activity of TRPV1 via a cGMP/PKG-dependent pathway in cultured rat dorsal root ganglion (DRG) neurons. NO donors, sodium nitroprusside (SNP) and S-nitro-N-acetylpenicillamine (SNAP), decreased capsaicin-evoked currents ($I_{cap}$). NO scavengers, hemoglobin and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO), prevented the inhibitory effect of SNP on $I_{cap}$. Membrane-permeable cGMP analogs, 8-bromoguanosine 3', 5'-cyclic monophosphate (8bromo-cGMP) and 8-(4chlorophenylthio)-guanosine 3',5'-cyclic monophosphate (8-pCPT-cGMP), and the guanylyl cyclase stimulator YC-1 mimicked the effect of SNP on $I_{cap}$. The PKG inhibitor KT5823 prevented the inhibition of $I_{cap}$ by SNP. These results suggest that NO can downregulate the function of TRPV1 through activation of the cGMP/PKG pathway in peripheral sensory neurons.

• 대한의생명과학회지
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• 제25권2호
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• pp.123-130
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• 2019

Platelet aggregation is essential for hemostatic process in case of blood vessels damages. However, excessive platelet aggregation can cause cardiovascular disorders including atherosclerosis, thrombosis and myocardial infarction. Scopoletin is usually found in the roots of genus Scopolia or Artemisia, and is known to have anticoagulant and anti-malarial effects. This study investigated the effect of scopoletin on human platelet aggregation induced by U46619, an analogue of thromboxane $A_2(TXA_2)$. Scopoletin had anti-platelet effects by down-regulating $TXA_2$ and intracellular $Ca^{2+}$ mobilization ($[Ca^{2+}]_i$), the aggregation-inducing molecules generated in activated platelets. On the other hand, scopoletin increased the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are known to be intracellular $Ca^{2+}$ antagonists. This resulted in inhibition of fibrinogen binding to ${\alpha}IIb/{\beta}_3$ in U46619-induced human platelet aggregation. In addition, scopoletin inhibited the release of adenosine trisphosphate (ATP) in dose-dependent manner. This result means that the aggregation amplification activity through the granule secretion in platelets was suppressed by scopoletin. Therefore, we demonstrated that scopoletin has a potent antiplatelet effect and is highly likely to prevent platelet-derived vascular disease.

• 생약학회지
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• 제52권1호
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• pp.26-33
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• 2021

During blood vessel damage, an essential step in the hemostatic process is platelet activation. However, it is important to properly control platelet activation, as various cardiovascular diseases, such as stroke, atherosclerosis, and myocardial infarction, are also caused by excessive platelet activation. Found primarily in the roots of plants of the genus Artemisia or Scopolia, isoscopoletin has been studied to demonstrate its potential pharmacological effects against Alzheimer's disease and anticancer, but the mechanisms and roles involved in thrombus formation and platelet aggregation are insufficient. This study investigated the effect of isoscopoletin on U46619-induced human platelet activation. As a result, isoscopoletin significantly increased the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) dose-dependently. In addition, isoscopoletin significantly phosphorylated inositol 1, 4, 5-triphosphate receptor (IP3R) and vasodilator-stimulated phosphprotein (VASP), which are known substrates for cAMP-dependent kinases and cGMP-dependent kinases. Phosphorylated IP3R by isoscopoletin inhibited Ca2+ mobilization from the dense tubular system Ca2+ channels to cytosol, and phosphorylated VASP was involved in the inhibition of fibrinogen binding through αIIb/β3 inactivation in the platelet membrane. Isoscopoletin finally reduced thrombin-induced fibrin clotting production. Therefore, this study suggests that isoscopoletin has a potent antiplatelet effect and may be helpful for platelet-related thrombotic diseases.

• 대한의생명과학회지
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• 제27권4호
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• pp.270-276
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• 2021

Physiological agents trigger a signaling process called "inside-out signaling" and activated platelets promote adhesion, granule release, and conformational changes of glycoprotein IIb/IIIa (αIIb/β₃). Activated αIIb/β₃ interacts with fibrinogen and initiates a second signaling step called "external signaling". These two signaling pathways can cause hemostasis or thrombosis, and thrombosis is a possible medical problem in arterial and venous vessels, and platelet-mediated thrombosis is a major cause of cardiovascular disease (CVD). Therefore, modulating platelet activity is important for platelet-mediated thrombosis and cardiovascular disease. Esculetin is a coumarin-based physiologically active 6,7-dihydroxy derivative known to have pharmacological activity against obesity, diabetes, renal failure and CVD. Although some studies have confirmed the effects of esculetin in human platelet activation and experimental mouse models, it is not clear how esculetin has antiplatelet and antithrombotic effects. We confirmed the effect and mechanism of action of escultein on human platelets induced by collagen. As a result, esculetin decreased Ca²⁺ recruitment through upregulation of inositol 1, 4, 5-triphosphate receptor. In addition, esculetin upregulates cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP)-dependent pathways and inhibits fibrinogen binding and thrombus contraction. Our results demonstrate the antiplatelet effect and antithrombotic effect of esculetin in human platelets. Therefore, we suggest that esculetin could be a potential phytochemical for the prevention of thrombus-mediated CVD.

• The Korean Journal of Physiology
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• 제26권1호
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• pp.15-25
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• 1992

In order to elucidate the properties of the background current whole cell patch clamp studies were performed in rabbit ventricular cells. Ramp pulses of ${\pm}80\;mV$ from holding potential of 40 mV(or 20 mV) at the speed of 0.8 V/sec were given every 30 sec(or 10 sec) and current-voltage diagrams(I-V curve) were obtained. For the activation of the background current isoprenaline, adenosine 3',5'-cyclic monophosphate(dBcAMP), guanosine 3',5'-cyclic monophosphate(cGMP), and $N^6$-2'-o-dibutyryladenosine 3',5'-cyclic monophosphate(dBcAMP) were applied after all known current systems were blocked with 2mM Ba, 1 mM Cd ,5 mM Ni, 10 ${\mu}M$ diltiazem, 10 ${\mu}m$ ouabain, and 20 mM tetraethylammonium(TEA). The conductance of background current in control was $0.65{\pm}0.69$ nS at 0 mV, its I-V curves was almost linear and reversed near 50 mV. When there was no taurine in pipette solution, isoprenaline hardly activated the background current but when taurine existed in pipette solution, isoprenaline activated the larger background current. Cyclic AMP or cyclic GMP alone had little effect on the activation of the background current, while cGMP potentiated cGMP effect. When the background current was activated with cGMP and cAMP, isoprenaline could not further increased the background current. The background current activated by isoprenaline depended on extracellular $Cl^-$ concentration and its reversal potential was shifted according to chloride equilibrium potential. The change of extracellular $Na+$ concentration had little effect on reversal potential of the background current activated by isoprenaline.

• Animal Bioscience
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• 제34권10호
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• pp.1684-1694
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• 2021

Objective: This study investigated the association between feed efficiency, physicochemical properties, flavor precursors and biomolecules in the thigh meat of Korat (KR) chickens. Methods: The feed intake and body weight of individual male KR chickens were recorded from 1 to 10 weeks old to calculate the individual residual feed intake (RFI) of 75 birds. At 10 weeks of age, chickens with the 10 highest (HRFI) and lowest RFI (LRFI) were slaughtered to provide thigh meat samples. The physicochemical properties (ultimate pH, water holding capacity [WHC], drip loss) and flavor precursors (guanosine monophosphate, inosine monophosphate (IMP), adenosine monophosphate and inosine) were analyzed conventionally, and Fourier transform infrared spectroscopy was used to identify the composition of biomolecules (lipids, ester lipids, amide I, amide II, amide III, and carbohydrates) and the secondary structure of the proteins. A group t-test was used to determine significant differences between mean values and principal component analysis to classify thigh meat samples into LRFI and HRFI KR chickens. Results: The physicochemical properties of thigh meat samples from LRFI and HRFI KR chickens were not significantly different but the IMP content, ratios of lipid, lipid ester, protein (amide I, amide II) were significantly different (p<0.05). The correlation loading results showed that the LRFI group was correlated with high ratios of lipids, lipid esters, collagen content (amide III) and beta sheet protein (rg loading >0.5) while the HRFI group was positively correlated with protein (amide I, amide II), alpha helix protein, IMP content, carbohydrate, ultimate pH and WHC (rg loading >0.5). Conclusion: The thigh meat from chickens with different RFI differed in physiochemical properties affecting meat texture, and in the contents of flavor precursors and biomolecules affecting the nutritional value of meat. This information can help animal breeders to make genetic improvements by taking more account of traits related to RFI.

• 한국식품과학회지
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• 제20권3호
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• pp.293-302
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• 1988

본 연구는 모과의 비휘발성 성분에 과한 조성을 규명하기 위한 기초 연구 과제로써 행하여졌다. 주요 비휘발성 성분은 유리 아미노산의 경우 valine, asparagin ${\gamma}-aminobutyric\;acid$, aspartic acid 와 serine 이 전체의 72%를 차지하고 arginine, tyrosine, methionine과 tryptophan은 거의 검출되지 않아다. Peptide 구성 아미노산으로는 주로 glutamic acid와 glutamine이었으며 cysteic acid, methione sulfone과 tryptophan은 검출되지 않았다. 핵산관련 물질의 분석 결과 cytosine, UMP, CMP는 소량 존재하셨으며 GMP, IMP, AMP는 검출되지 않았다. 당 분석결과 주성분은 glucose, sorbose, sucrose, fructose였으며 fructose 함량이 가장 높은 것으로 판명되었다. GC 및 GC-MS방법에 의해 총 11성분의 유기산이 동정 되었으며 이들중 tartaric acid및 ${\alpha}-ketoglutaric\;acid$가 주성분이었다. 정량된 총 비타민 C 함량은 386.6 mg%였으며 ascorbic-acid dehydroascorbic acid와 2,3-diketo-L-gulonic acid는 각각 28.8mg%, 154.5mg%, 197.3mg%였다. 무기성분으로는 칼슘과 인이 주요 성분으로 나타났으며 카드뮴, 구리, 납은 소량 존재하였다. 모과의 천연 및 합성 extract에 대한 관능검사의 결과 유리형, 아미노산, 당, 유기산, 비타민 C및 무기질의 맛의 주성분으로 판명되었다. 따라서 모과의 향미 성분 중 비휘발성 성분은 주로 상기 다섯 그룹에 의해서 나타남을 확인하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권5호
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• pp.402-407
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• 2006

Vascular endothelial cells release proteinases that degrade the extracellular matrix (ECM), thus enabling cell migration during angiogenesis and vasculogenesis. Sildenafil citrate stimulates the nitric oxide-cyclic guanosine monophosphate pathway through inhibition of phosphodiesterase type V (PDE5). In this report, we examined the mechanisms underlying sildenafil citrate-induced cell migration using cultured mouse aortic endothelial cells (MAECs). Sildenafil citrate induced migration and proteinase secretion by murine endothelial cells. Sildenafil citrate induced the secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9, which is inhibited by $NF-{\kappa}B$ inhibitors. Sildenafil citrate also induced the secretion of plasmin, which is inhibited by PI 3'-kinase inhibitors. It is suggested that sildenafil citrate-induced migrating activity in endothelial cells may be accomplished by increased secretion of proteinases.