ABSTRACT
A double quenching molecular beacon ( MB) with simple structure was designed based on organic quencher and G bases, and a simple detection method for thrombin was developed using this MB. In this MB, FAM and BHQ-1 were selected as fluorophore and organic quencher, three continuous nucleotides with G base were connected with BHQ-1, and the loop of MB was designed as a nucleic acid aptamer of thrombin. In the absence of thrombin, the MB was in the stem-loop structure, the fluorophore FAM was close to BHQ-1 and G bases, the fluorescence of FAM was dual quenched by BHQ-1 and G bases, and the fluorescence signal of FAM was very weak. In the presence of thrombin, MB specifically bound thrombin and formed a G-quadruplex structure. The stem-loop structure of the MB was destroyed, and FAM was separated with BHQ-1 and G bases, leading to recovery of fluorescence of FAM. Under the optimal conditions, the fluorescence intensity of FAM exhibited a good linear relationship with concentration of thrombin in the range of 0. 4-40. 0 nmol/L, and regression equation was △I=24. 63C (nmol/L)+ 13. 06 (R2 =0. 9972) with the detection limit of 0. 18 nmol/L (3σ, n=9). The average recoveries of this method in serum samples were 96. 3%-98. 7%, which indicated that the method had high accuracy.
ABSTRACT
A double quenching molecular beacon ( MB) with simple structure was designed based on organic quencher and G bases, and a simple detection method for thrombin was developed using this MB. In this MB, FAM and BHQ-1 were selected as fluorophore and organic quencher, three continuous nucleotides with G base were connected with BHQ-1, and the loop of MB was designed as a nucleic acid aptamer of thrombin. In the absence of thrombin, the MB was in the stem-loop structure, the fluorophore FAM was close to BHQ-1 and G bases, the fluorescence of FAM was dual quenched by BHQ-1 and G bases, and the fluorescence signal of FAM was very weak. In the presence of thrombin, MB specifically bound thrombin and formed a G-quadruplex structure. The stem-loop structure of the MB was destroyed, and FAM was separated with BHQ-1 and G bases, leading to recovery of fluorescence of FAM. Under the optimal conditions, the fluorescence intensity of FAM exhibited a good linear relationship with concentration of thrombin in the range of 0. 4-40. 0 nmol/L, and regression equation was △I=24. 63C (nmol/L)+ 13. 06 (R2 =0. 9972) with the detection limit of 0. 18 nmol/L (3σ, n=9). The average recoveries of this method in serum samples were 96. 3%-98. 7%, which indicated that the method had high accuracy.
ABSTRACT
Objective To investigate the protective mechanism of protein kinase C(PKC)and calcium sensing receptor(CaR)in ischemia preconditioned rat hearts.Methods Using cell culture method,in vitro cultured inhibitor(IPC+CaRI).Apoptosis was detected using TUNEL and Hoechst33342 cell viability was detected by MTT,the protein expression of easpase-12,calpain and CaR in endochylema were detected using Wedtetm blot.ResultsIn I/R group nucleus was shrank,big blue,chromatin concentrated,apoptotle body appeared.Other groups haddifferent fluorescence intensity varying degree,IPC+PKCI+CaRS group had more big blue nucleus.Myocardialcell viability and apoptotic rate,I/R group[(62.99±0.65)%,(19.13±0.87)%],IPC group[(78.67±0.37)%,(14.21±0.74)%],IPC+PKCI group[(71.09±0.52)%,(20.46±0.81)%],IPC+PKCI+CaRS group(66.10±0.75)%,(24.89±1.43)%],IPC+CaRS group[(69.56±0.44)%,(21.64±0.77)%],IPC+CaRI group(85.81±0.60)%,(13.12±0.69)%],all had a difference(P＜0.05 or＜0.01)compared with C group[(100.00)%,(6.02±0. 31)%].Western blot identified that CaR expression in IPC+PKCI and IPC+CaRS,IPC+PKCI+CaRS groupswas more than that in IPC and IPC+CaRI groups;easpase-12 had more active fragment(60×103)in I/R,IPC+CaRS,IPC+PKCI+CaRS groups;ealpain expressions in I/R,IPC,IPC+PKCI,IPC+PKCI+CaRS,IPC+CaRSgroups were higher than those in C and IPC+CaRI,I/R group was the highest one,C group the second,IPC+CaRI the third.Conclusion The interaction of PKC and CaR can reduce the intracellular Ca2+ from sarcoplasmicreticulum thus provide a protection.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the role of calcium-sensing receptor (CaR) on ischemia/reperfusion-induced rat cardiomyocyte apoptosis.</p><p><b>METHODS</b>The isolated rat hearts were subjected to 40 min ischemia followed by 2h of reperfusion with or without CaR agonist GdCl3 at the beginning of reperfusion. Control hearts (without ischemia) and ischemic hearts (40 min ischemia without reperfusion) served as controls. The protein expressions of CaR, Bcl-2 and cyt C were detected by Western blot. Cardiomyocyte apoptosis was detected by TUNEL. Mitochondrial potential (Deltaphim) was detected by laser confocal microscopy.</p><p><b>RESULTS</b>Compared to controls groups, the expressions of CaR and apoptotic cells were significantly increased, Deltaphim and expressions of mitochondria cyt C and Bcl-2 were significantly reduced in ischemia/reperfusion hearts with or without GdCl3.</p><p><b>CONCLUSION</b>CaR was involved in the induction of cardiomyocyte apoptosis during ischemia/reperfusion via mitochondrial pathway.</p>
Subject(s)
Animals , Female , Male , Rats , Apoptosis , Disease Models, Animal , Mitochondria, Heart , Metabolism , Myocardial Ischemia , Metabolism , Myocardial Reperfusion Injury , Metabolism , Myocytes, Cardiac , Cell Biology , Rats, Wistar , Receptors, Calcium-Sensing , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between calcium-sensing receptor protein (CaSR) expression and rat cardiomyocyte apoptosis and related signal transduction pathways.</p><p><b>METHODS</b>The CaSR, BCl2, Caspase3 protein and ERK1/2 phosphorylation or non-phosphorylation were detected by Western blot. Cardiomyocyte apoptosis was detected by flow cytometry and immunofluorescence.</p><p><b>RESULTS</b>CaSR protein was detected in rat cardiac tissue and CaSR activator gadolinium (GdCl3) induced cardiomyocyte apoptosis and increased ERK1/2 phosphorylation and expression of BCl2 and activated Caspase3. The selective mitogen-activated protein kinase (MAPK) inhibitor PD98059 abolished gadolinium -induced ERK1/2 activation and BCl2 expression, further increased the activation of Caspase3 and cardiomyocyte apoptosis.</p><p><b>CONCLUSION</b>Our results demonstrate the CaSR existence in cardiomyocytes and CaSR activation by gadolinium can induce myocyte apoptosis by activating Caspase3 and tyrosine protein kinase pathway.</p>