血管紧张素转换酶(ACE)抑制肽的酶法制备

以扇贝裙边的酶解产物——蛋白多肽对ACE活性的抑制率作为控制水解程度的指标,确定制备ACE活性抑制肽的最佳酶种及酶解工艺技术条件.通过胰蛋白酶、胃蛋白酶、木瓜蛋白酶、复合风味酶、枯草杆菌蛋白酶5种酶酶解扇贝裙边得到的蛋白多肽对ACE抑制能力的比较发现,5种酶在不同酶解时间所得到的酶解蛋白多肽都具有一定的ACE抑制能力,其中胃蛋白酶酶解蛋白多肽的ACE抑制率最高,为91.33%;再经L9(3)4正交实验对胃蛋白酶酶解工艺条件进行优化,确定酶解反应最佳条件是酶量400 U.g-底1物,pH 2.5,温度32℃,底物浓度(原料∶水)1∶2,酶解时间3 h;试验结果还表明,单酶(胃蛋白酶)的酶解蛋白多肽比复合酶(复合风味酶)和双酶(胃蛋白酶 木瓜蛋白酶)的酶解蛋白多肽对ACE活性的抑制能力都强.     

罗非鱼鱼鳞胶原多肽的优化制备及其生物活性研究

以罗非鱼鱼鳞为原料,采用碱性蛋白酶和胰蛋白酶复合水解,在单因素试验的基础上,采用响应面法优化酶解工艺,制备鱼鳞胶原多肽.测定胶原多肽的抗氧化活性、细菌低温保护活性、氨基酸组成及相对分子质量分布.结果显示,最适酶解条件为:底物质量浓度30.6 mg·m L-1、胰蛋白酶和碱性蛋白的加酶量分别为1.44和0.70 mg·m L-1、酶解温度50℃、pH值8.5、酶解时间6.35 h.酶解胶原多肽对DPPH自由基和羟基自由基的半数清除质量浓度(IC50)分别为2.89和3.54 mg·m L-1.经过细菌低温保护试验,当胶原多肽质量浓度为1 mg·m L-1时,嗜热链球菌的存活率达到75.6%.鱼鳞胶原肽相对分子质量分布显示,78%多肽片段的相对分子质量分布于180~2 000 u之间.氨基酸组成分析显示鱼鳞多肽富含甘氨酸、丙氨酸、脯氨酸、羟脯氨酸及天冬氨酸等,这些特定的氨基酸与胶原多肽的抗氧化活性、细菌低温保护活性相关.     

胃蛋白酶前处理对大豆蛋白酶解特性的影响

为了改善大豆蛋白酶解效果,采用胃蛋白酶对自制碱溶酸沉的大豆蛋白酶解2h使其球蛋白组分水解,之后继续用Alcalase和Protamex酶解,并用SDS-PAGE和GPC对酶解产物的分子质量分布进行分析.结果显示:与未使用胃蛋白酶处理的单酶酶解相比,胃蛋白酶前处理可提高大豆蛋白回收率和水解度及酶解产物的抗氧化能力指数( ORAC值),最高分别为95.4％、23.1％和1078.6,提高了39.9％、35.9％和38.5％;使用胃蛋白酶前处理的酶解产物分子质量绝大部分在10ku以下,其中大部分在1～5ku之间.以上结果表明:胃蛋白酶前处理能促进大豆蛋白的酶解并增强酶解产物的抗氧化活性.     

响应面法优化胃蛋白酶制备蛋清多肽的研究

以蛋清粉为原料,以酶解液的抗氧化能力为指标,优化了胃蛋白酶酶解蛋清粉的工艺条件。单因素实验结果表明,酶解温度50℃、酶解pH值2.5和质量分数5%的蛋清粉,经酶解后可以获得较佳的抗氧化能力;响应面实验结果表明,在pH值2.1、蛋清粉质量分数3.5%、反应温度49℃时,酶解液产生的多肽具有最优的抗氧化活性。研究结果为进一步开发蛋清多肽打下了一定的基础。     

文蛤蛋白水解制备抗氧化活性肽的研究

以文蛤蛋白为原料,通过蛋白酶水解制备抗氧化活性肽.利用体外清除DPPH活性评价酶解产物的抗氧化活性,采用超滤、葡聚糖凝胶柱层析和HPLC对相应的活性肽进行分离纯化,通过HPLC-MS进行结构鉴定.结果表明:木瓜蛋白酶水解产物的DPPH清除活性明显高于碱性蛋白酶、风味蛋白酶、中性蛋白酶和复合蛋白酶,产物质量浓度为1 mg·mL-1时,DPPH清除率为55.74%;以DPPH清除率为筛选指标,对木瓜蛋白酶酶解产物进行逐级分离,得到4个具有抗氧化活性的目的肽段,氨基酸序列分别为LNFNLEKSR(1120.3 u)、SWLRPR(814.4 u)、RIGNIISQY(1063.3 u)和LNFNLEK(877.2 u).     

鲍鱼内脏多糖的提取、纯化及其抗氧化和抑菌活性

以皱纹盘鲍(Haliotis discus hannai Ino)内脏为实验材料,采用碱性蛋白酶、中性蛋白酶、酸性蛋白酶、胃蛋白酶、胰蛋白酶和木瓜蛋白酶6种蛋白酶对其进行酶解提取多糖,结果显示碱性蛋白酶酶解所得多糖得率最高,为6.66%,进而由单因素试验和正交试验确定了碱性蛋白酶提取鲍鱼内脏多糖的最佳工艺条件.将得到的鲍鱼内脏粗多糖进行体外抗氧化活性测定,结果显示:100%清除羟自由基、100%清除2,2-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二氨盐(ABTS)自由基以及700 nm处吸光度(A_(700))为0.485时代表的还原能力对应的鲍鱼内脏粗多糖质量浓度分别为9.6,7.5,8.2 mg/mL,表明所得粗多糖具有较好的抗氧化活性.采用双酶解法以提高多糖含量,结果显示胃蛋白酶二次酶解所得的多糖含量最高,且多糖样品在3种抗氧化活性模型中均具有很好的效果.采用Sevage法和反复冻融法去除蛋白,过氧化氢脱除色素,进一步纯化得到高纯度的鲍鱼内脏多糖,并采用双层平板法测定其抑菌活性,结果表明其对金黄色葡萄球菌(Staphyloccocus aureus)、鼠伤寒沙门氏菌(Salmonella typhimurium)、大肠杆菌(Escherichia coil)和铜绿假单胞菌(Pseudomonas aeruginosa)都具有较好的抑制作用.     

北冬虫夏草多肽分离纯化及活性研究

目的对北冬虫夏草活性多肽进行分离纯化,并测定其抗氧化活性.方法优选北冬虫夏草多肽的提取方法;通过体外抗氧化DPPH清除率测定北冬虫夏草多肽的抗氧化活性;通过大孔树脂HP-20对北冬虫夏草多肽产物进行分离纯化,并分别测定洗脱后各浓度产物的蛋白含量和抗氧化活性,经Tricine-SDS-PAGE电泳法初步鉴定北冬虫夏草中多肽的分子量.结果 Tris-HCl作为提取液时DPPH清除率最高可达88.68%;经大孔树脂HP-20洗脱并分离纯化后,25%浓度的乙醇溶液和去离子水可作为洗脱剂; Tricine-SDS-PAGE结果显示:北冬虫夏草中富含小分子肽.结论此研究确定了北冬虫夏草多肽的最佳提取工艺,提高了初步提取多肽的产量;北冬虫夏草中的多肽具有一定的抗氧化活性.     

文冠果降血压肽的制备及其活性研究

以文冠果蛋白为研究对象,采用酶解法制备文冠果蛋白酶解肽,并对其体外抗高血压活性进行研究。以水解度为指标确定酶解条件。蛋白水解物经超滤得到分子量为1k Da,1~5 k Da和5 k Da 3个区段的多肽组分,测定其对血管紧张素转化酶(Angiotensin Converting Enzyme,ACE)的抑制率。最佳酶解条件为:底物质量浓度40g/L,加酶量8%(质量分数)(碱性蛋白酶),酶解时间175 min,酶解温度55℃和酶解p H 9.0,此条件下水解度最高为22.97%;3种多肽组分中1k Da的ACE抑制率最高为83.43%,其半抑制浓度(50%inhibitory concentration,IC50)为0.394 mg/m L。文冠果蛋白酶解多肽具有显著的体外抗ACE活性,可作为降血压肽的开发原料。     

鳙鱼活性多肽酶法制备工艺研究

为优化鳙鱼活性多肽酶法制备工艺,分析了鳙鱼肉糜预处理温度和酶解温度对水解度的影响,确定了最佳的预处理条件为85℃水浴中加热预处理20 min,酶解温度设为55～75℃.经均匀设计实验优选和最优条件验证实验证实,以氮溶指数为指标的最优酶解条件为:酶解时间8.0 h,固液比1∶4.25,蛋白酶A用量3‰,酶解温度75℃,产物氮溶指数达80.54%;以多肽得率为指标的最优酶解条件为:酶解时间8.0 h,固液比1∶2,蛋白酶A用量3‰,酶解温度75℃,产物多肽得率达11.92%;以产物总抗氧化指数为指标的最优酶解条件为:酶解时间1.0 h,固液比1∶6,蛋白酶A用量3‰,酶解温度55℃,所得产物总抗氧化指数达87.42‰.     

复合酶降解羽毛粉的效果研究

运用物理法与酶解法相结合的方法,对一种复合酶的酶解效率进行了研究.羽毛粉经高温高压处理后,采用不同复合酶浓度和不同酶解时间对羽毛粉样品进行酶解,通过测定其中的可溶性蛋白质含量、胃蛋白酶消化率来考察其酶解效率,并且对酶解上清液中多肽和氨基酸进行初步的分析.研究结果表明,该复合酶在一定的条件下可有效降解羽毛产生的多肽、寡肽和游离氨基酸,并且酶解上清液中多肽和氨基酸的分子量均在6 kDa以下.     

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.     

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。     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.