响应面法优化香菇多糖的超声辅助提取工艺

为了开发利用香菇资源,采用超声辅助法提取香菇中的多糖,利用响应面法优化超声辅助提取法提取香菇多糖的工艺条件。首先进行单因素试验考察,在单因素试验的基础上,选择超声波功率、超声时间及料液比为自变量,以多糖得率为响应值,采用Box-Benhnken法设计3因素3水平响应面设计试验。结果表明,响应面模型与实际情况拟合良好,能较好地预测香菇多糖得率。最佳工艺:超声波功率300 W、超声波处理时间25 min、料液比1∶30,多糖得率25.71%,与理论值(25.55%)相比,相对误差较小,为0.63%。与传统热水浸提法比较,超声波提取法多糖得率较高,且耗时少,是理想的香菇多糖提取方法。     

响应面分析法优化超声波辅助提取芦笋多糖工艺条件的研究

采用超声波辅助水提法提取芦笋多糖,并用响应面法进行工艺条件优化研究.结果表明芦笋多糖得率为4.298%,其最佳工艺条件为提取超声功率250 w,料液比为l:30(g:ml),超声温度为75℃,超声时间为60 min.     

响应面法优化超声辅助提取太子参多糖工艺研究

本文探讨超声波作用下太子参多糖提取的最佳工艺条件。在单因素试验基础上,采用响应面法对太子参多糖提取工艺参数进行优化研究。响应面试验表明提取温度、提取时间和水料比对响应值多糖提取得率均有显著影响,优化得到太子参多糖超声提取最佳工艺条件为:提取温度为74℃;提取时间为65 min;水料比为26 mL/g;超声波功率100 W。在此条件下太子参多糖的提取得率为2.48%,与模型预测值非常接近。     

超声波法提取大枣多糖工艺的优化

为了进一步提高大枣多糖的提取效率,本文通过正交试验优化了超声波法提取大枣多糖的工艺条件。考察的因素包括料液比、超声功率、超声时间和浸提温度。结果显示超声波法提取大枣多糖的最佳提取工艺条件为:料液比1∶30、超声功率80W、超声时间10min,浸提温度80℃。在此工艺条件下大枣多糖的提取率达到6.97%。该工艺条件下提取率较高,因此适合于提取大枣中的多糖类化合物。     

蕨菜多糖超声波辅助提取及其药理活性初步研究

为优化蕨菜多糖的提取工艺,同时检测蕨菜多糖的药理学活性。实验采用超声波辅助提取法,在单因素试验的基础上,考察液料比、浸提次数、超声浸提时间、超声功率四因素对蕨菜多糖提取得率的影响。运用Design Expect 10.0软件分析,通过响应面分析法(RSM)优化提取条件,对蕨菜多糖促进小鼠脾细胞增殖能力和抑制结肠癌细胞(HTC-8)增殖能力进行分析。结果表明:蕨菜多糖的优化提取工艺为:液料比:36.2∶1;浸提次数:4次;超声浸提时间:43.1 min;超声波功率:240 W,在此条件下,蕨菜多糖提取效果最好,提取得率达8.60%。各因素对多糖提取得率的影响程度:浸提次数>液料比>超声浸提时间>超声功率。通过药理活性研究表明,本实验获得的蕨菜多糖具有脾细胞免疫增值和抑制结肠癌细胞增殖活性。     

地木耳粗多糖超声波辅助提取工艺优化及其动力学和热力学分析

本文探讨了超声波辅助提取地木耳粗多糖的工艺条件,以多糖得率为考察指标,料液比、超声温度、超声功率和超声时间为试验因素,通过单因素试验和Box-Behnken试验设计对工艺条件进行了优化。在此基础上,建立了以Fick第二定律为基础的粗多糖提取动力学模型,并求解出速率常数、相对萃余率及活化能等关键模型参数,并研究了提取过程的热力学特性。结果表明,地木耳粗多糖的最佳超声波提取工艺条件为:料液比为1/50 g/m L,温度为350.15 K,功率为540 W,时间为25 min,在此条件下粗多糖得率达到13.07%。该提取过程符合一级动力学模型,且试验数据与动力学模型计算值吻合良好。热力学分析显示该提取过程是一个逆反应自发进行的吸热过程。     

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。     

响应面法优化梨小豆粗多糖超声波提取工艺研究

本文以梨小豆为原料,在单因素试验的基础上,采用响应面法优化超声波辅助提取梨小豆粗多糖的工艺技术参数,研究超声波功率、液料比、超声温度、超声时间等单因素对梨小豆粗多糖提取效果的影响,通过SAS8.2统计分析系统对响应面实验结果进行分析,结果显示:超声功率254 W,液料比25.5∶1 m L/g,超声温度78.4℃,超声时间26.2 min,梨小豆粗多糖的得率达到0.34±0.015%,与模型预测值接近。     

超声辅助提取杜仲多糖及其抗氧化活性

以杜仲树皮为原料,采用超声辅助法提取杜仲多糖,考察了预浸泡时间、超声功率、超声时间、超声温度、料液比和提取次数对杜仲多糖得率的影响,最佳提取条件为:预浸泡时间2 h,超声功率250 W,超声时间30 min,超声温度40℃,料液比1∶12 g·mL-1,提取次数2次。在上述提取条件下提取杜仲多糖,多糖得率为1.94%。此外,对杜仲多糖的抗氧化活性进行了分析评价。结果表明,在相同浓度下,杜仲多糖对DPPH自由基的清除能力高于维生素C。然而,杜仲多糖的铁还原能力低于维生素C的铁还原能力,并且与浓度呈正相关。     

响应面优化超声辅助提取刺梨多糖工艺研究

探讨超声波作用下刺梨多糖提取的最佳工艺条件。在单因素试验基础上,采用响应面法对刺梨多糖提取工艺参数进行优化研究。响应面试验表明提取温度、超声功率、超声时间、液料比对响应值刺梨多糖提取率均有显著影响,优化得到超声辅助提取刺梨多糖最佳工艺条件为:超声时间30 min,超声功率120 W,液料比40m L/g,提取温度80℃,提取3次。在此条件下的刺梨多糖提取率可达2.18%,与模型预测值非常接近。     

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.