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。     

菊苣基生叶中总黄酮提取工艺的研究

采用分光光度法,以亚硝酸钠、硝酸铝、氢氧化钠为试剂,芦丁为对照品,乙醇回流提取菊苣基生叶中总黄酮.在提取过程中,通过单因素实验分析了乙醇浓度、回流温度、回流时间及料液比等4个主要因素对提取率的影响.在单因素的基础上,通过正交实验,得到最佳提取工艺为:乙醇浓度为70%,料液比1:40,回流温度80℃,回流时间为2h.实验结果可靠,方法简便,最佳条件适合批量生产中该药材的提取.     

新疆菊苣籽中总黄酮提取工艺研究

目的:以芦丁为标准品,采用分光光度法测定菊苣籽中总黄酮含量 .方法:在提取过程中通 过单因素实验,分析了乙醇浓度、回流温度、提取时间及料液比等四个因素对提取 率的影响.在单因素实验的基础上建立正交实验,优化菊苣籽总黄酮提取工艺条件.结果: 在最佳吸收波长512nm处,菊苣籽最佳提取工艺条件为乙醇浓度70%,料液比1∶50, 回流温 度70℃,提取时间2h,最佳黄酮含量C为3.80%.结论:以芦丁为对照品 ,用紫外可见分光光度法测定菊苣籽中总黄酮含量,方法简单,准确度较高.     

锈毛莓总黄酮的提取工艺优化

采用乙醇回流提取法,对提取温度、乙醇浓度、时间、料液比进行单因素考察,结合正交试验,确定锈毛莓总黄酮最佳提取工艺。结果显示,最佳提取工艺为料液比1∶25、乙醇浓度60%、提取温度70 ℃、提取时间2.5 h,提取2次,总黄酮得率可达6.78%。     

超声波法提取短毛柽柳中总黄酮

目的：测定短毛柽柳中的总黄酮含量并确定其提取条件。方法：在提取过程中通过单因素实验分析了料液比、超声时间、乙醇浓度及超声温度等主要因素对提取率的影响。在此基础上通过正交设计法进行实验,优化短毛柽柳黄酮提取工艺条件。结果：短毛柽柳总黄酮的最佳提取工艺条件为料液比为1∶15,超声处理时间为40min,乙醇浓度为45%,超声温度50℃。根据实验测得的短毛柽柳总黄酮平均得率为33.675mg/g,含量为22.75%。结论：实验结果可靠、方法简便、省时且无污染,是提取短毛柽柳中黄酮化合物的有效途径。     

正交实验优选月腺大戟根总黄酮的提取工艺

目的：研究月腺大戟根中总黄酮类化合物的提取工艺,为研发新型植物源农药提供理论基础。方法：采用索氏提取法对月腺大戟根总黄酮进行提取,以乙醇体积分数、提取时间、提取温度、料液比为实验因素,以提取的总黄酮含量为指标,对提取工艺进行考察,确定最佳提取条件。结果和结论：根总黄酮提取的优化条件为：提取时间2h,提取温度70℃,料液比1：40,乙醇浓度50％;影响提取的主次顺序为：料液比〉提取时间〉乙醇浓度〉提取温度;其中料液比和提取时间是影响根总黄酮提取效果的显著因素。     

竹柏叶总黄酮不同提取方法比较

本研究采用正交试验设计分别优选回流提取和超声波提取竹柏叶总黄酮的最佳工艺条件。在单因素试验的基础上,以总黄酮得率为参考指标,选取液料比、乙醇体积分数、温度和时间4个影响因子,进行正交试验,分别确立回流提取和超声波提取最佳提取工艺条件。结果表明,回流提取优化工艺条件为:液料比30∶1(m L∶g),乙醇体积分数为70%,回流时间1.0 h,回流温度80℃;超声波提取优化工艺为:液料比25∶1(m L∶g),乙醇体积分数为70%,超声时间30 min,超声水浴温度60℃。两种提取方法的最终提取效果比较,回流提取的总黄酮得率为15.522%,超声波提取总黄酮得率为13.637%,回流提取法总黄酮得率高于超声波提取法。本实验结果为后续竹柏叶总黄酮的开发利用提供了参考。     

甘青铁线莲花中黄酮类化合物提取工艺探讨

对甘青铁线莲花中黄酮类物质的提取工艺进行研究。结果表明：在温度为80℃时,影响黄酮类化合物提取的因素顺序为提取时间〉乙醇浓度〉料液比。甘青铁线莲花中黄酮类物质的最佳提取条件为：当温度为80℃时,乙醇浓度80％、料液比1：30（g：mL）、回流时间为1．5h时提取最佳。在此条件下总黄酮的得率为1．86％。     

均质剪切辅助响应面法提取扛板归总黄酮及其抗氧化性能研究

为了研究扛板归中总黄酮的最佳提取工艺及其体外抗氧化活性,在高剪切及回流提取单因素的基础上,采用响应面法考察了回流温度、回流时间、料液比、乙醇浓度对提取率的影响。结果显示,扛板归总黄酮最优提取工艺为:回流温度79.86℃,回流时间2.03 h,乙醇浓度51.64%,料液比1∶59(m∶V),剪切次数7次,剪切温度50℃。最优工艺下总黄酮的提取率为8.37%。提取的总黄酮抗氧化性能良好,浓度为8 mg/mL时,对DPPH·、O■和·OH三种自由基的清除率在68%～90%之间。     

莲子心总黄酮的超声波萃取工艺研究

研究了超声波萃取法从莲子心中提取总黄酮的最佳工艺。通过单因素控制法和正交试验,以乙醇为溶剂,总黄酮提取率为考察指标,在超声波辅助下研究了乙醇浓度、提取时间、料液比和提取温度对总黄酮提取率的影响。结果表明影响莲子心中总黄酮提取率的主要因素是乙醇的浓度,其次依次为提取温度、料液比、超声波萃取时间;提取的最佳条件是:乙醇的浓度为60%,提取温度是70℃,料液比为1:24,超声波萃取时间为30 min,此条件下得到的总黄酮的提取率是10.86 mg/g。     

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.