葡萄皮多酚的提取、纯化及组成研究

以巨峰葡萄皮为原料,采用超声波辅助提取法,研究葡萄皮多酚的提取工艺,并用响应面法进行优化,进一步通过HPLC法确定多酚的组成和含量。得出最佳的提取工艺参数为：料液比1∶40、超声时间1.6h、超声功率430W、乙醇浓度33%,提取率为29.16 mg/g;AB-8型大孔吸附树脂对葡萄多酚分离效果良好;在葡萄皮酚类物质中确定了10种单体酚,其中主要酚类物质为儿茶素,含量为15.74±0.21μg/mg。     

刺葡萄籽中多酚的超声波提取及提取物中齐墩果酸的含量分析

本文研究了超声波法提取刺葡萄籽中多酚类物质的方法,考察了提取剂、提取时间、料液比等因素对提取率的影响。结果表明,用超声波法进行多酚类物质提取的最佳工艺条件为：以70％的丙酮水溶液为提取剂,料液比为1：10,室温下超声波提取两次,每次30min。采用Folin—Ciocaheau方法测定粗提物中多酚的含量,得出刺葡萄籽多酚粗提物得率为4．95％,纯度为49．89％。本文还对多酚粗提物中活性成分齐墩果酸进行了进一步的分离、鉴定与检测。     

红松多酚物质的提取工艺及其抗炎活性初步研究

选取超声波提取法对红松树皮中多酚类物质的提取工艺进行研究,以多酚提取率作为指标,采用单因素试验及正交试验,研究了物料比、乙醇浓度、提取时间、提取温度对红松多酚提取的影响。结果表明,超声波提取的最佳工艺条件是:物料比(g·m L~(-1))1∶30,乙醇浓度60%,提取时间2.0 h,提取温度80℃。本文也对红松多酚的抗炎作用进行了研究,并与杨树多酚、蓝莓多酚进行了比较,结果表明,在0.01~100μg·m L~(-1)范围内,3种多酚都有一定的抗炎作用,且抗炎作用大小顺序为:蓝莓多酚红松多酚杨树多酚。     

葡萄叶中总黄酮的提取工艺研究

目的：从葡萄叶中提取总黄酮。方法：采用正交试验法研究葡萄叶总黄酮的最佳提取工艺条件,考察了乙醇浓度、回流温度、回流时间及料液比四因素对葡萄叶总黄酮提取率的影响。结果：确立了葡萄叶总黄酮最佳提取条件为：45％的乙醇为溶剂、液料比为1：40、提取温度为60％、提取时间2h,在最佳工艺条件下葡萄叶总黄酮含量为5．329mg／g。     

响应面优化细叶杜香提取工艺及抗氧化活性研究

研究细叶杜香抗氧化物质的最佳提取工艺及提取物的抗氧化性能。在单因素试验基础上,选择提取时间、提取温度及料液比为影响因子,应用Box-Benhnken中心组合法进行3因素3水平试验设计,以1,1-二苯基-2-三硝基苯肼(DPPH)清除率为响应值,进行响应面分析,并研究提取物的体外抗氧化活性。结合实际操作,得到最佳提取条件为提取时间3.3 h、提取温度69℃、料液比为1∶23,在该条件下提取液的DPPH自由基清除率为84.37±0.17%,接近预测值。抗氧化物质得率为4.68±0.24 g/100 g,总黄酮含量为236.17±2.16 mg/g,多酚含量为73.97±3.18mg/g。抗氧化活性实验结果表明,细叶杜香提取物具有较好的抗氧化活性。     

二次旋转正交法优化提取板栗壳斗中多酚类物质的工艺及其抗氧化性研究

为实现二次旋转正交法优化提取板栗壳斗中多酚类抗氧化剂,本文用板栗壳为原材料,采用传统水液溶解和加热提取的工艺,以单因素的结果设计二次旋转正交实验,以总多酚提取率为评定对象,得出板栗壳中多酚提取的最佳工艺条件,并对产品进行了抗氧化测试和光谱分析。实验结果表明,板栗壳多酚的最佳工艺条件为:乙醇浓度57%,提取温度85℃,提取时间45 min。在该条件下,板栗壳多酚的最佳提取率为5.44%。当多酚浓度为1 mg/m L时,产品对羟基自由基清除率为8.15%。产品的红外光谱和紫外光谱均符合多酚类物质的光谱特征。     

从柿叶中提取多酚的研究

以柿叶为材料,以总多酚的提取率为考察指标,采用Folin-Ciocalteu法对柿叶总多酚含量进行了测定,并采用超声技术通过单因素实验(乙醇浓度、料液比、温度及时间)和正交实验对柿叶中多酚类物质的提取工艺进行探讨.确定柿叶中多酚类物质的最佳超声提取工艺条件为:用40%的乙醇溶液,按1:40的料液比,在50℃下提取20min.在此条件下总多酚的提取率可达5.69%.     

牡丹花多酚提取优化与抗氧化性

目的:为探明牡丹花多酚提取的最佳工艺以及多酚的抗氧化性。方法:在单因素的基础上采用响应曲面法的中心组合设计以牡丹花为材料,并利用DPPH自由基清除法研究牡丹花多酚的抗氧化性。结果:牡丹花多酚提取的最佳条件为提取温度70℃,提取时间44min、乙醇浓度48.7%,在此试验条件下多酚实际得率可达130.672mgGAE/mL。抗氧化性试验表明牡丹花多酚的DPPH自由基清除率大于BHT,小于Vc。结论:该最佳提取条件提高牡丹花多酚得率,且多酚具有较强的抗氧化性。     

新疆石榴皮多酚的提取及其对酪氨酸酶的抑制作用

优化新疆石榴皮多酚的提取工艺,并研究石榴皮提取物对酪氨酸酶的抑制作用。采用超声波辅助法提取石榴皮多酚,通过单因素试验和正交试验确定其最佳提取工艺条件:丙酮体积分数70%、超声波功率200 W、提取温度40℃、料液比1∶35 g/m L、提取时间50 min、提取2次,在此条件下石榴皮多酚得率为23.77 mg/g。同时测定了石榴皮多酚提取物对蘑菇酪氨酸酶的抑制活性,石榴皮多酚提取物质量浓度在12 mg/m L时,对酪氨酸酶活力的相对抑制率为44.05%。该研究为从石榴皮中提取天然酪氨酸酶抑制剂提供了实验依据。     

超声波辅助提取田基黄多酚类和黄酮类化合物及其抗氧化活性研究(英文)

采用超声技术从田基黄中提取活性物质。运用响应面法确定超声提取田基黄的最佳条件。运用单因素试验选取三个自变量。采用Box-Behnken设计评价这三个自变量对总黄酮和总多酚提取、DPPH和ABTS+活性清除的影响。通过方差分析显示,二次模型对反应的贡献率具有统计学意义。运用响应面法进行最优化研究,并用数学模型绘制出三维响应面。通过结合反应得出最佳试验条件:超声时间48.89 min,乙醇浓度63.72%,超声温度66.92℃。总黄酮值为105.06 mg RE/g DW,总多酚值为51.75 mg GAE/g DW,%DPPHsc为58.81%,%ABTSsc为64.99%。在最佳试验条件下,试验值与方差分析预测值一致。结果表明,采用四个模型和响应面法优化总黄酮和总多酚的提取、DPPH和ABTS+活性清除是切实可行的。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.