蛋清肽酶解工艺及血管紧张素转化酶抑制活性研究

采用酶法制备蛋清肽,色谱纯化ACE抑制活性组分并鉴定其一级结构.通过考察底物质量分数、加酶量、酶解温度和pH值对水解度的影响,结合多元线性回归设计和二次回归正交组合设计建立蛋清ACE抑制肽酶解工艺模型,并经液相色谱串联质谱鉴定其一级结构.结果表明:最佳酶解工艺为底物质量分数8%、pH值10.73、加酶量12.14%及酶解温度56.80℃,酶解物纯化后半抑制质量浓度为0.18 mg/mL.液相色谱串联质谱鉴定高活性组分中3种活性肽一级结构,氨基酸序列分别为Arg-Val-Pro-Ser-Leu-Met、Thr-Pro-Ser-Pro-Arg和Asp-Leu-Gln-Gly-Lys.     

蛋清肽酶解工艺及血管紧张素转化酶抑制活性研究

采用酶法制备蛋清肽,色谱纯化ACE抑制活性组分并鉴定其一级结构。通过考察底物质量分数、加酶量、酶解温度和pH值对水解度的影响,结合多元线性回归设计和二次回归正交组合设计建立蛋清ACE抑制肽酶解工艺模型,并经液相色谱串联质谱鉴定其一级结构。结果表明：最佳酶解工艺为底物质量分数8%、pH值10.73、加酶量12.14%及酶解温度56.80℃,酶解物纯化后半抑制质量浓度为0.18mg/mL。液相色谱串联质谱鉴定高活性组分中3种活性肽一级结构,氨基酸序列分别为     

酪蛋白水解物的酶法修饰优化与抗氧化活性改善

利用木瓜蛋白酶对酪蛋白水解,并对所得到的水解物进行类蛋白反应修饰,制备高活性抗氧化肽.以水解物的游离氨基含量变化为响应值,利用响应面分析法对类蛋白反应条件进行优化,得到适宜条件为:酶添加量为500 U/g,温度30℃,底物质量分数50%,反应时间5.6 h.毛细管电泳分析确认,水解物经类蛋白反应修饰后肽分子组成发生变化.抗氧化活性分析结果表明,所制备的3个修饰产物对3种自由基的清除能力显著提高.     

植酸酶高产菌株的筛选与酶的分离纯化及性质研究

从土壤中筛选到一株植酸酶高产菌株,利用紫外线对该菌株进行诱变提高植酸酶产量,并采用硫酸铵分级沉淀、DEAE-纤维素阴离子交换层析和Sephadex G-100凝胶过滤层析对植酸酶进行分离纯化。酶学性质研究表明,该酶的最适pH值为5．0,最适温度约为50℃。     

植酸酶高产菌株的筛选与酶的分离纯化及性质研究

从土壤中筛选到一株植酸酶高产菌株,利用紫外线对该菌株进行诱变提高植酸酶产量,并采用硫酸铵分级沉淀、DEAE-纤维素阴离子交换层析和Sephadex G-100凝胶过滤层析对植酸酶进行分离纯化。酶学性质研究表明,该酶的最适pH值为5.0,最适温度约为50℃。     

花生肽的提取纯化及生物活性研究进展

花生肽是花生蛋白经水解或发酵的产物,不仅具有较高的营养价值,而且还具有抗氧化、降血压、抗菌等生物活性。本文综述了国内外对花生肽提取纯化的方法,并对花生肽的生物活性进行概述。     

荧光法与紫外法检测水产品中磺胺类药物的比较研究

采用液相色谱紫外检测法和液相色谱柱后衍生荧光检测法测定水产品中磺胺类药物的残留量.结果表明,液相色谱柱后衍生荧光检测法磺胺8种的回收率为86.1％～98.5％,精密度为1.5％～3.3％,检出限低为5μg/kg;杂质干扰少,方法简便、快捷,灵敏.     

玉米肽研究进展

玉米蛋白肽在抗氧化和降血压、血脂、胆固醇方面具有显著效果。根据国内外相关研究进展,介绍玉米肽的主要制备提取方法,以及各提取方法的原理、优势和缺点,展望玉米肽的开发应用前景,为玉米肽的应用和开发研究提供理论参考。     

野生酸枣果硒多糖纯化与光谱分析

采用热水浸提、乙醇沉淀法获得酸枣果硒多糖粗品.苯酚-硫酸法测其多糖含量为(92.6±4.72) mg/g,原子荧光光度法测其硒含量为( 17.8±2.05)μg/kg.DEAE-25纤维素和Sephadex G-75凝胶层析柱进一步分离纯化得白色絮状多糖.薄层层析和高效阴离子交换色谱法分析其单糖组成.结果表明:该多糖是由鼠李糖、阿拉伯糖、半乳糖、葡萄糖、木糖等单糖组成,其摩尔比为3.21∶8.36∶5.61∶0.96∶1.82.红外光谱分析表明具有明显的多糖特征吸收峰,核磁共振波谱表明该多糖结构主要为β-糖苷键连接的吡喃型葡聚糖.     

生物活性肽的制备及分离纯化研究

近年来,生物活性肽的应用越来越广泛,因此本文综述了最近几年国内外在生物活性肽方面的研究成果,较为全面地介绍了制备生物活性肽的原料、方法及其分离纯化。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。