By introduction of a new Fe(L^(1))_(2)spin-crossover(SCO)unit into the polynuclear system,a nano-scale Fe4(L^(2))_(4)molecular square architecture is designed through coordination-directed self-assembly strategy.Both ...By introduction of a new Fe(L^(1))_(2)spin-crossover(SCO)unit into the polynuclear system,a nano-scale Fe4(L^(2))_(4)molecular square architecture is designed through coordination-directed self-assembly strategy.Both the mononuclear Fe(L^(1))_(2)and tetranuclear Fe4(L^(2))_(4)complexes have bee门structurally confirmed by 1H nuclear magnetic resonance(NMR),electrospray ionization time-of-flight mass spectrometry(ESI-TOF-MS),and temperature-dependent single crystal X-ray diffraction studies.Variable-temperature magnetic susceptibility measurements reveal the presence of an abrupt SCO behavior with a thermal hysteresis width of 4K for Fe(L^(1))_(2).By clear contrast,Fe4(L^(2))_(4)undergoes a gradual spin transition behavior with enlarged thermal hysteresis width and higher spin transition temperature.展开更多
To explore a novel strategy for antisense gene therapy of cancer,the coding sequence of hum an proliferating cell nuclear antigen(PCNA) c DNA was reversely inserted into the eukaryotic vector p L XSN by molecular cl...To explore a novel strategy for antisense gene therapy of cancer,the coding sequence of hum an proliferating cell nuclear antigen(PCNA) c DNA was reversely inserted into the eukaryotic vector p L XSN by molecular cloning techniques and transferred into bladder cancer EJcells with li- posome. The PCNA expression in transferred cells was dynamically detected by immunofluo- rescence and RT- PCR techniques. Changes of proliferation activities of cancer cells were assayed by MTT colorim etric and cloning formation m ethods.In the experiment,the antisense eukaryotic vector was successfully constructed and nam ed as p L APSN.After transfection with it for1- 7 days,PCNA protein and m RNA levels in cancer cells were blocked by16 .74 % - 84 .2 1% (P< 0 .0 5 ) and2 3.2 7% - 86 .15 % (P<0 .0 5 ) respectively.The proliferation activities of transferred cells were inhibited by 2 7.91% - 6 2 .0 7% (P<0 .0 1) ,with cloning formation abilities being de- creased by 5 0 .81% (P<0 .0 1) . Itwas concluded that the in vitro proliferation activities of cancer cells could be effectively inhibited by blocking PCNA expression with antisense technique,which could serve as an ideal strategy for gene therapy of bladder cancer.展开更多
分子动力学模拟是研究包括RNA在内的生物大分子结构和功能的重要方法,但常规的显式溶剂模拟耗时较长,影响了其进一步应用。隐式溶剂模型通过用连续模型代替溶剂分子,能大大加速模拟速度,因此提高模拟效率。然而,现有的隐式溶剂模型都不...分子动力学模拟是研究包括RNA在内的生物大分子结构和功能的重要方法,但常规的显式溶剂模拟耗时较长,影响了其进一步应用。隐式溶剂模型通过用连续模型代替溶剂分子,能大大加速模拟速度,因此提高模拟效率。然而,现有的隐式溶剂模型都不能很好地描述核酸分子,尤其是RNA。在之前的研究中(已接收),我们提出了一个新的隐式溶剂模型,并分别测试了A型RNA双螺旋、28S r RNA和t RNA等多个系统,验证了该模型可以更好地计算隐式溶剂下的静电相互作用。由于上述系统均以稳定的结构作为起始,因此没有采集到大的构象变化。在本文中,我们将采用B型RNA双螺旋(B-RNA)作为测试系统来验证该模型是否能正确地采集到大尺度的构象转变过程。初步结果表明,在我们的模型下,B-RNA不仅能够正确地采集A型RNA双链构象,而且其搜索速度也比相应的显式模型快。展开更多
基金the National Natural Science Foundation of China(Nos.21825107,21971237,21801241)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000).
文摘By introduction of a new Fe(L^(1))_(2)spin-crossover(SCO)unit into the polynuclear system,a nano-scale Fe4(L^(2))_(4)molecular square architecture is designed through coordination-directed self-assembly strategy.Both the mononuclear Fe(L^(1))_(2)and tetranuclear Fe4(L^(2))_(4)complexes have bee门structurally confirmed by 1H nuclear magnetic resonance(NMR),electrospray ionization time-of-flight mass spectrometry(ESI-TOF-MS),and temperature-dependent single crystal X-ray diffraction studies.Variable-temperature magnetic susceptibility measurements reveal the presence of an abrupt SCO behavior with a thermal hysteresis width of 4K for Fe(L^(1))_(2).By clear contrast,Fe4(L^(2))_(4)undergoes a gradual spin transition behavior with enlarged thermal hysteresis width and higher spin transition temperature.
基金This studywassupported by a grant from the NationalNatural Sciences Foundation ofChina(No. 39770 739)
文摘To explore a novel strategy for antisense gene therapy of cancer,the coding sequence of hum an proliferating cell nuclear antigen(PCNA) c DNA was reversely inserted into the eukaryotic vector p L XSN by molecular cloning techniques and transferred into bladder cancer EJcells with li- posome. The PCNA expression in transferred cells was dynamically detected by immunofluo- rescence and RT- PCR techniques. Changes of proliferation activities of cancer cells were assayed by MTT colorim etric and cloning formation m ethods.In the experiment,the antisense eukaryotic vector was successfully constructed and nam ed as p L APSN.After transfection with it for1- 7 days,PCNA protein and m RNA levels in cancer cells were blocked by16 .74 % - 84 .2 1% (P< 0 .0 5 ) and2 3.2 7% - 86 .15 % (P<0 .0 5 ) respectively.The proliferation activities of transferred cells were inhibited by 2 7.91% - 6 2 .0 7% (P<0 .0 1) ,with cloning formation abilities being de- creased by 5 0 .81% (P<0 .0 1) . Itwas concluded that the in vitro proliferation activities of cancer cells could be effectively inhibited by blocking PCNA expression with antisense technique,which could serve as an ideal strategy for gene therapy of bladder cancer.
文摘分子动力学模拟是研究包括RNA在内的生物大分子结构和功能的重要方法,但常规的显式溶剂模拟耗时较长,影响了其进一步应用。隐式溶剂模型通过用连续模型代替溶剂分子,能大大加速模拟速度,因此提高模拟效率。然而,现有的隐式溶剂模型都不能很好地描述核酸分子,尤其是RNA。在之前的研究中(已接收),我们提出了一个新的隐式溶剂模型,并分别测试了A型RNA双螺旋、28S r RNA和t RNA等多个系统,验证了该模型可以更好地计算隐式溶剂下的静电相互作用。由于上述系统均以稳定的结构作为起始,因此没有采集到大的构象变化。在本文中,我们将采用B型RNA双螺旋(B-RNA)作为测试系统来验证该模型是否能正确地采集到大尺度的构象转变过程。初步结果表明,在我们的模型下,B-RNA不仅能够正确地采集A型RNA双链构象,而且其搜索速度也比相应的显式模型快。
