柴胡皂甙促大鼠胰腺腺泡酶分泌作用的特征及胞外Ca2+对其的影响

利用检测胰腺腺泡蛋白分泌量表征胰酶分泌 ,研究柴胡总皂甙及柴胡皂甙单体 促胰腺腺泡酶分泌的量效特征和时效特征 ,并探讨胞外 Ca2 浓度的影响 .结果表明柴胡总皂甙及柴胡皂甙单体 促酶分泌作用随浓度增加而增强 ,且趋向饱和 .柴胡总皂甙促泌作用动力学呈现早期的高促分泌相和随后的低促分泌相 ;而 1 0 - 5 mol/L柴胡皂甙单体 的促泌动力学则出现了前期的低促分泌相 .胞外 Ca2 浓度为零 ,降低了柴胡总皂甙低促泌相的作用 ,并致使腺泡分泌趋向停止 .     

CW2M3分泌新型淀粉酶的最适条件及酶的应用条件

从原筛选的产酶菌株CW2出发,经多次紫外诱变、初筛和复筛后,获得了变异菌株CW2M3,其产酶水平为原菌株的332.7%,且具有良好的遗传稳定性.薄层层析证明,CW2M3分泌的新型淀粉酶能有效地催化淀粉降解产生异麦芽低聚糖,产物主要包括异麦芽糖、潘糖、异麦芽三糖等.用正交法结合薄层层析法确定了各因素对CW2M3产酶水平的影响,结果表明,培养温度是显著因素,CW2M3的最适产酶条件为:用牛肉膏培养基(牛肉膏0.7%、蛋白胨0.7%、 NaCl 0.5%、Ph 7.0)培养,温度40 ℃,时间12 h.用该酶催化淀粉转化为异麦芽低聚糖时,酶促反应时间和温度均是显著影响因素,酶催化淀粉降解的最适条件为:温度65 ℃,酶促反应1.0 h,体系Ph为7.0.     

平滑肌肌球蛋白轻链激酶对肌球蛋白非Ca2 依赖性磷酸化(2)

为了初步揭示肌球蛋白轻链激酶(MLCK)对肌球蛋白(myosin)非Ca2 依赖性磷酸化的特征 试验方法采用10%甘油聚丙烯酰胺凝胶电泳检测myosin的磷酸化,用孔雀绿法测定myosin Mg2 -ATP酶活性及选择Scoin Image扫描软件分析所获得的数据。提出在MLCK参与的myosin活性调节中,myosin以非磷酸化、非Ca2 依赖性(CIPM)及Ca2 依赖性磷酸化(CDPM) 种状态存在 研究发现非Ca2 依赖性磷酸化myosin有以下特征:(1)耗能(Mg2 -ATP酶活性)高于非磷酸化myosin但低于Ca2 依赖性磷酸化myosin;(2)花生四烯酸(AA)可选择性加强myosin非Ca2 依赖性磷酸化;(3)在本试验条件下,未观察到MLCK抑制剂ML-9对非Ca2 依赖性myosin磷酸化的抑制作用;(4)组胺(histamine)对非Ca2 依赖性的抑制小于对Ca2 依赖性磷酸化的抑制,且这些差异在统计学上有显著性。以上结果提示myosin非Ca2 依赖性磷酸化不仅在程度上,而且在机制上与Ca2 依赖性磷酸化可能存在重要区别     

ATP刺激巨噬细胞[Ca2+]i升高和氧自由基增加及大黄酸的抑制作用研究

研究了ATP刺激的大鼠腹腔巨噬细胞[Ca2 ]i升高与氧自由基(ROS)产生的关系和大黄酸抑制作用特征.提取大鼠腹腔巨噬细胞,利用Ca2 探针Fura-2检测单细胞胞内自由Ca2 浓度([Ca2 ]i)变化,同时利用NBT还原反应强度检测同一细胞ROS产生能力.结果发现无ATP刺激的巨噬细胞的ROS产生量较低;1mmol/L ATP刺激巨噬细胞单细胞后诱发[Ca2 ]i显著升高由胞内Ca2 释放和胞外Ca2 内流组成,同时ROS产生增强2倍;胞外无Ca2 条件下ROS产生随着[Ca2 ]i下降而减少.10-5和10-4mol/L浓度大黄酸对1mmol/L ATP刺激巨噬细胞单细胞的[Ca2 ]i升高和ROS产生有剂量依赖性的抑制作用;多细胞的统计分析表明10-5和10-4mol/L浓度大黄酸分别抑制了[Ca2 ]i峰值的49%和84%,同时抑制了ROS产生的59%和81%.因此认为ATP刺激大鼠腹腔巨噬细胞诱发的[Ca2 ]i升高介导了ROS的产生,大黄酸剂量依赖性的抑制ATP刺激的细胞[Ca2 ]i升高和ROS产生能力,并提示大黄酸抑制细胞[Ca2 ]i升高是其抑制ROS产生的重要机制.     

金属离子对青霉葡萄糖氧化酶的效应研究

研究了几种金属离子对青霉(Penicillium amagasakiense)葡萄糖氧化酶(简称GOD,EC.1.1.3.4)活力的影响.金属离子对酶活力的影响表明:Na+、K+、Ca2+、Pb2+、Mn2+等对酶活力基本没有影响;Al3+、Zn2+对酶有一定的激活作用;Ag+、Hg2+、Mg2+、Cd2+、Cu2+、Co2+等对该酶活力有不同程度的抑制作用.其中Ag+、Cu2+、Hg2+对酶的抑制作用较强,随着抑制剂浓度增大,酶活力呈指数下降,导致酶活力下降50%的抑制浓度为0.08、10.0 和31.25 μmol/L.进一步研究了Ag+的抑制动力学,结果显示:Ag+对酶的抑制作用为竞争性可逆抑制,抑制常数(KI)为0.065 μmol/L.该研究对青霉葡萄糖氧化酶的应用具有一定的参考价值.     

三丁基锡对罗非鱼稚鱼生长和ATP酶活力的影响

在实验生态条件下,研究浓度为0.1、1、10 ng/L的三丁基锡对罗非鱼稚鱼生长、死亡率及Ca2 -ATP酶和Na ,K -ATP酶活力的影响.结果显示:三丁基锡抑制罗非鱼稚鱼的生长发育.其中15 d的1 ng/L和10 ng/L暴露组体长较对照组显著性降低;15 d和30 d的10 ng/L暴露组死亡率较对照组均显著增加.三丁基锡对罗非鱼稚鱼的Ca2 -ATP酶和Na ,K -ATP酶活力的抑制均表现剂量依赖性.Ca2 -ATP酶和Na ,K -ATP酶活力的变化与死亡率具有一定相关性.     

IDO抑制剂PCC0208009在结肠癌CT26荷瘤小鼠的PK/PD研究

通过研究吲哚胺2,3-双加氧酶(IDO)抑制剂PCC0208009在结肠癌CT26荷瘤小鼠中的药代动力学(PK)和药效动力学(PD)特点,为后续IDO抑制剂的开发和临床治疗效果的预测提供参考依据.研究采用结肠癌CT26荷瘤小鼠,以Kyn/Trp为药效评价指标,考察IDO抑制剂PCC0208009在小鼠体内的药代动力学(PK)与药效动力学(PD)特点及相关性.单次灌胃给予200 mg/kg PCC0208009,药物在血浆中的T_(max)、T_(1/2)、平均C_(max)和AUC_(0-last)分别为0.25 h、6.22 h、13.3μg/mL和22.9 h·μg/mL,在肿瘤中分别为0.5h、7.08 h、13.3μg/mL和17.5 h·μg/g;PCC0208009在给药后2～8 h内可有效抑制血浆和肿瘤中Kyn/Trp.单次或多次灌胃给予25-400 mg/kg PCC0208009 4 h时,PCC0208009在血浆和肿瘤中的药物浓度以及对Kyn/Trp的抑制作用均呈剂量依赖性.结果表明,PCC0208009在给药后2～8 h内能有效抑制荷瘤小鼠血浆和肿瘤的IDO活性,在血浆和肿瘤中的药物浓度及对IDO的抑制作用均呈剂量依赖性,PK和PD间具有较好的相关性.     

锌离子对酶法测定抑制作用的研究

基于乳酸脱氢酶(LDH)催化乳酸和氧化型烟酰胺腺嘌呤二核苷酸(NAD)的反应,在最佳酶反应条件下,研究了金属离子对酶催化的抑制作用.发现Zn2 对LDH的酶促反应有显著的抑制,抑制常数KQS为13mmol/L,属非竞争性抑制.根据在抑制剂作用下的米氏方程,可以利用酶法对锌离子进行定量测定.通过加入金属离子络合剂乙二胺四乙酸(EDTA)进行了干扰消除实验,结果表明:可有效消除一定浓度的Zn2 对LDH酶促反应测定底物的干扰.     

大豆荚膜过氧化物酶催化硫醚反应动力学模型

用大豆荚膜过氧化物酶(Soybean Pod Peroxidase, SPP)在微乳液中催化不对称氧化反应,在酶活性为3 200 U/mL,50 ℃时反应5 h,产率为91.56%,对映体过量值为96.08%.SPP催化奥美拉唑硫醚不对称氧化反应生成S-奥美拉唑,其反应机制包括酶催化的SPP-I双电子还原反应、SPP-I单电子转移反应和非酶催化的化学反应.建立的动力学模型很好地拟合了试验数据,其平均相对偏差为5.44%.酶促反应动力学机制为带底物产物抑制的乒乓机制,而化学反应遵循幂律,过氧化氢产生底物抑制,S-奥美拉唑产生产物抑制.     

秋茄叶缩合单宁对蘑菇酪氨酸酶的抑制机理

研究了红树植物秋茄叶缩合单宁对蘑菇酪氨酸酶单酚酶活力和二酚酶活力的影响和抑制动力学.结果表明秋茄叶缩合单宁不仅可以降低蘑菇酪氨酸酶单酚酶酶促反应的稳定态活力,也可以延长反应的迟滞时间,并具有浓度依赖关系,随着抑制剂浓度增大,稳定态活力下降,迟滞时间延长.当抑制剂质量浓度达33.00μg/mL时,稳定态活力从100%下降到74%,迟滞时间从32.7s增加到72.9s;秋茄叶缩合单宁对二酚酶的抑制也显示浓度效应,抑制效果显著,引起酶活力下降50%的抑制剂质量浓度(IC50)为30.00μg/mL,其对二酚酶的抑制显示可逆的效应,抑制类型为混合型,对游离酶的抑制常数(KI)为25.05μg/mL和对酶-底物络合物的抑制常数(KIS)为46.69μg/mL.本研究揭示了植物秋茄叶缩合单宁作为一种新型酪氨酸酶抑制剂的可能性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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