一种改进的漆酶酶活检测方法

以 2 ,2′ -连氮 -双 (3-乙基苯并噻唑 - 6 -磺酸铵 ) (简称ABTS)为漆酶A、B的底物 ,采用UV - 2 2 0 1型紫外 -可见分光光度计连续记录酶反应在 2 5℃ ,4 2 0nm波长下的时间历程曲线 ,并求取最初部分的斜率以计算漆酶酶活的方法 .该方法直观、方便、准确且可靠 .在 2 5℃的 0 .0 4mol/LBritton Robinson缓冲溶液中 ,漆酶A、B的最适 pH值分别为 4 .0和 4 .5 .在 2 5℃最适 pH值的Britton Robinson缓冲液中 ,由双倒数作图法求得漆酶A、B的米氏常数Km 分别是 6 .6 4× 1 0 - 5mol/L和 2 .2 1× 1 0 - 5mol/L ,漆酶A、B的最大米氏反应速度Vmax分别是 1 4 2 5μmol.M (L·min)和 32 5μmol.M (L·min) .漆酶A、B的酶活分别为 2 2 99μmol·min- 1·L- 1和 1 1 4 8μmol·min- 1·L- 1.     

乙酰胆碱酯酶膜的酶学性质及其对有机磷农药的检测效果

测定自行制备的乙酰胆碱酯酶(AChE)酶液和壳聚糖-AChE酶膜的酶学性质,并以壳聚糖-AChE酶膜分别检测乐果、甲胺磷、敌百虫、敌敌畏、甲基对硫磷5种有机磷农药,探讨采取酶膜进行快速检测有机磷农药残留的可行性.结果显示:壳聚糖-AChE酶膜的KappM为2.8×10-4mol/L,最适pH值为8.0,在pH值为8.0～8.5时活力稳定;最适反应温度为45℃左右,在15～60℃时较为稳定;半衰期达12d,固定化酶膜的实际应用性能较游离酶有较大改善.壳聚糖-AChE酶膜对不同类型的有机磷农药的敏感性差异很大,对甲基对硫磷最为敏感,其pI50为5.57,对其它4种农药pI50为4.0左右;以酶活力抑制率16%为农药检出标准,甲基对硫磷的检出限为0.4mmg/L,其他4种检出限为3～22mg/L,只有甲基对硫磷达到检测要求.     

酿酒酵母中D-(-)-扁桃酸脱氢酶性质研究

采用DEAE Sepharose离子交换层析、Butyl Sepharose疏水层析和Blue Sepharose亲和层析等分离方法,从高产D-(-)-扁桃酸的酵母菌株BY1.1b中纯化得到电泳纯的D-(-)-扁桃酸脱氢酶.采用Sephacryl S-200分子筛层析柱测得该酶的相对分子质量约60 kDa,用SDS-PAGE电泳测得该酶亚基分子量为32 kDa,表明该酶属于同型二聚体.该酶的最适反应温度为30℃,最适反应pH为6.0.该酶在低于30℃,pH5.5~8.0较为稳定.以NADH和苯乙酮酸为底物,其Km值分别为Km(NADH)=99.2μmol/L和Km(苯乙酮酸)=263.3μmol/L.     

南美白对虾丝氨酸蛋白酶的分离纯化及性质研究

通过硫酸铵盐析、DEAE-Sepharose、Phenyl-Sepharose、Hydroxyapatite、Superdex 75等方法,从南美白对虾消化腺中分离得到一种丝氨酸蛋白酶.SDS-PAGE结果显示,其分子质量约为28 ku,最适pH值与最适温度分别为9.0和40℃,且pH值在7.0~10.0之间以及温度在40℃以下有较高的稳定性.底物特异性实验与抑制剂实验结果表明,该酶属于类胰蛋白酶的丝氨酸蛋白酶.动力学实验显示,以Boc-Phe-Ser-Arg-MCA为底物时,Km=0.69μmol/L,Kcat=0.33 S-1,Kcat/Km=4.78×105(mol/L)-1S-1.     

玻璃纤维素壳聚糖膜固定乙酰胆碱酯酶的研究

以玻璃纤维素壳聚糖膜为载体,戊二醛为交联剂,进行乙酰胆碱酯酶(AChE)的固定,并对固定化酶的理化性质进行研究.结果表明,乙酰胆碱酯酶的较佳固定化条件为:150 U/mL AChE液50μL,体积分数为5%的戊二醛溶液50μL,质量分数为1%的BSA100μL,pH值为8.0的0.2 mol/L PBS缓冲液,配制成1 mL酶液,玻璃纤维素壳聚糖膜浸于此酶液4℃固定8 h.固定化酶的最适作用温度37℃,最适pH 8.0,能够重复利用4次以上,表明该固定化酶的稳定性较高.     

伯克霍尔德菌ZYB002胞外脂肪酶的分离纯化及其酶学性质分析

伯克霍尔德菌ZYB002胞外脂肪酶发酵上清液经冻干、透析、DEAE Sepharose Fast Flow层析柱和Sephadex G-75层析柱等步骤纯化后,获得电泳纯的脂肪酶.纯化后的脂肪酶分子质量为33 ku,水解棕榈酸对硝基苯的比活力为1 902.5 U·mg-1.脂肪酶催化水解反应的最适温度和最适pH值分别为50℃和8.5;在30~65℃和pH 3.0~10.0的范围内保持相对稳定.脂肪酶对烷烃、非离子型表面活性剂等有机溶剂具有较好的耐受性.在最适条件下,脂肪酶水解pNPP的Km和Vmax分别为3.79 mmol·L-1和714.29μmol·mg-1·min-1.     

青枯雷尔氏菌龙胆酸1,2-双加氧酶基因的克隆、表达和酶性质的研究

本研究克隆、表达了青枯雷尔氏菌GMI1000菌株中编码龙胆酸1,2-双加氧酶的基因, 并通过亲和层析对该酶进行了纯化, SDS-PAGE结果表明该酶亚基约为38kDa.该酶的最适反应温度和最适pH分别为30℃和7.5.该酶的Km为56μmol/L,pI为4.6～4.8.纯化后的龙胆酸1,2-双加氧高度不稳定:4℃下放置72h即失去85%的酶活. 甘油和β-巯基乙醇可稳定该酶酶活,在添加10%(体积比)甘油至酶液(50mmol/L, pH 7.3的磷酸盐缓冲液保存)后,-20℃保藏2周后均能检出明显的酶活.0.1～1mmol/L Fe2 可以激活或者稳定该酶的酶活.Na ,K ,Mg2 和Ca2 (分别为1～2mmol/L)对该酶的酶活无明显的影响.Mn2 ,Zn2 和Fe3 的添加量超过2mmol/L时,酶活急剧下降.1mmol/L的Cu2 即使该酶失去酶活.     

假单胞菌TS-1138 L-半胱氨酸脱巯基酶的纯化和性质研究

假单胞菌TS-1138L-半胱氨酸脱巯基酶经DEAECellulose-52阶段洗脱、SephadexG-100柱层析被纯化了80.3倍,SDS-PAGE鉴定为单一条带,该酶的相对分子质量为53.0kDa;酶反应的最适pH为7.5,最适反应温度为35℃,该酶的米氏常数为2.37μmol/L,最大反应速度为0.11μmol/mL·min·Pb2+对该酶有很强的激活作用,Zn2+对该酶有较强的抑制作用,羟胺为该酶特异性的抑制剂.     

鲍鱼碱性磷酸酶的分离纯化和性质研究

以杂色鲍(Haliotis diversicolor)内脏为原料,经Tris HCl缓冲液(pH 7.5,含0.1mol/L NaCl)抽提,正丁醇处理,硫酸铵分级沉淀分离,DE 32离子交换、Sephadex G 150分子筛、DE 32纯化,得到电泳单一纯的碱性磷酸酶制剂,比活力为1 226 U/mg.酶学性质和动力学性质研究表明:该酶催化对硝基苯磷酸水解反应的最适 pH值为 10.08,最适温度为48℃.米氏常数Km 值为0.80 mmol/L,Vm 值为20.1 mmol/L·min-1(pH 10.0,37℃).酶的热稳定性研究表明:该酶在pH 7~11区间和在温度低于55℃下稳定.金属离子对酶活力的影响结果表明:Li+、Na+和K+对酶活力没有影响,Mg2+、Ca2+、Ba2+、Mn2+和Co2+对酶有不同程度的激活作用,而Cu2+、Cd2+、Zn2+、Hg2+、Ag+、Bi2+和Pb2+等对酶起抑制作用.     

蝾螺(Turbo cornutus Solander)N-乙酰-β-D-氨基葡萄糖苷酶的分离纯化及性质的初步研究

以蝾螺内脏为材料,通过硫酸铵沉淀分级分离、SephadexG 200分子筛柱层析和两次DEAE SephadexA 50离子交换柱层析纯化,获得聚丙烯酰胺凝胶电泳单一纯的N 乙酰 β D 氨基葡萄糖苷酶酶制剂.纯酶的比活力为1448U·mg-1.酶的紫外特征吸收峰在275nm处,内源荧光发射峰在340nm处.以对 硝基苯 N 乙酰 β D 氨基葡萄糖为底物,研究酶催化底物水解的反应动力学,结果表明:酶的最适pH为4.5,最适温度为45℃.该酶在pH3.5～6.0区域较稳定,而在pH>7能很快失活;在40℃以下处理30min,酶活力保持稳定,高于40℃,酶稳定性较差,很快失活.酶促反应动力学符合米氏双曲线方程,测得米氏常数Km为3.13mmol·L-1,最大反应速度Vm为17.68μmol·L-1·min-1.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.