超声-酶法提取两面针中别隐品碱的工艺优选

以别隐品碱提取率为指标,先考察提取溶剂加酸和酶解预处理对两面针超声提取的适用性,再用正交试验优化超声功率、提取次数和溶剂量,最后动态过程优化超声提取时间。结果证明提取溶剂p H≤3不利于别隐品碱的提取。最佳工艺条件为:复合酶预处理后,以体积分数60%乙醇超声(250 W)提取3次,第1次以7倍量溶剂提取18 min,第2次以3倍量溶剂提取12 min,第3次以2倍量溶剂提取12 min,别隐品碱提取率为89.5%。该工艺经济、高效、节能、省时,可为开发利用别隐品碱提供实验基础。     

超声波法优选苦豆子中总黄酮的提取工艺研究

目的:超声波法优选苦豆子中总黄酮的提取工艺。方法:以超声波为提取方法,以总黄酮提取率为考察指标,选取乙醇浓度(体积分数)、加溶剂倍量和超声时间为考察因素,采用均匀实验和正交实验,优选苦豆子中总黄酮的提取工艺。结果:影响总黄酮提取率各因素主次为:ACB,确定最佳提取工艺为A2B3C3,即70%乙醇,加溶剂40倍量,超声提取75 min。结论:采用该工艺提取苦豆子中总黄酮,提取率较高且稳定,说明该工艺合理可行。     

乌头须根总生物碱提取工艺的考察

目的:考察乌头须根中总生物碱的最佳提取工艺条件。方法:酸碱滴定法测定乌头须根中总生物碱含量,以总生物碱提取率为指标,采用L9(3)~4正交实验法筛选乌头须根总生物碱的最佳提取工艺。结果:乌头须根总生物碱含量为1.094%,影响提取的主次因素为:乙醇浓度>提取次数>提取时间>乙醇用量;优选得到的最佳提取工艺为A_3B_1C_3D_3,即以8倍量80%的乙醇提取3次,每次1.5小时。结论:乌头须根总生物碱含量较高,提取工艺条件稳定、经济、可行。     

两面针生物碱不同提取方法的比较

复合酶预处理两面针药材后,以氯化两面针碱、总生物碱得率和干膏收率为指标,采用正交试验和动态过程优化半仿生-超声法、渗漉法和回流法提取工艺,对其提取效果进行比较。各以4倍量枸橼酸-三乙胺60%乙醇缓冲液(p H 2.0、7.5和8.3)为溶剂,依次超声(250 W)提取15、12和9 min,氯化两面针碱得率2.52‰,总生物碱得率2.15%,干膏收率16.14%。以60%乙醇(5 g/L盐酸)为溶剂,浸润10 min后以10mL/min流速渗漉16倍量溶剂,氯化两面针碱得率2.30‰,总生物碱得率2.18%,干膏收率14.86%。分别用6、5和4倍量60%乙醇(5 g/L盐酸)依次回流15、12和9 min,氯化两面针碱得率2.46‰,总生物碱得率2.36%,干膏收率15.37%。半仿生-超声法和渗漉法比回流法经济,可为工业生产提供参考依据。     

桑黄菌丝体粗多糖的提取方法研究

采用正交试验设计,以桑黄菌丝体粗多糖含量为考察指标,用苯酚—硫酸法,分别确定了热水浸提法、微波辅助提取法和超声提取法的最佳工艺。通过极差分析得出:热水浸提法的最优工艺为浸提时间3 h、浸提3次、液料质量比50∶1、浸提温度90℃,粗多糖提取率为2.10%;微波提取法的最优工艺为微波处理15 min、液料质量比50∶1、提取3次,提取率为4.18%;超声提取法的最优工艺为超声30 min、提取2次、液料质量比60∶1、温度60℃、频率60 Hz,提取率为3.02%。微波辅助法与热水浸提法相比,时间缩短,且提取率提高近1倍;与超声提取法相比,时间缩短1/2,但提取率提高40%。因此,微波辅助提取法速度更快、提取效率更高、操作更简便,优于其他2种方法。     

Box-Behnken响应面法优化芦笋总皂苷超声提取工艺

优选芦笋总皂苷的超声提取工艺,以总皂苷含量为指标,在单因素试验基础上,通过Box-Behnken响应面法考察乙醇体积分数、料液比、超声时间和温度对提取工艺的影响。最佳超声提取工艺为加15倍量74%乙醇于50℃超声提取54 min;总皂苷平均质量分数13.059%(RSD 1.63%),与预测值(13.185%)的偏差较小。优选的提取工艺稳定可行,为芦笋总皂苷的开发应用提供实验依据。     

正交试验法优化吴茱萸总碱的微波提取

以紫外-可见分光光度法为检测手段,研究了乙醇-水混合溶剂中吴茱萸总生物碱的微波提取条件,试验中分别以微波功率、萃取时间和萃取溶剂的用量、浓度及酸度等为因素,设计了五因素四水平的正交试验,考察了它们对总生物碱成分提取率的影响。结果表明,最佳提取条件为：在700W微波功率下,用浓度70％、酸度pH=2的乙醇-水混合溶剂25mL／g,提取6min,此条件下总生物碱的提取率可达0．4898％。     

响应曲面法优化伊贝母总生物碱提取工艺

目的:采用响应曲面法(Box-Behnken)优化伊贝母中总生物碱的提取工艺。方法:在单因素试验基础上,选取乙醇体积分数、提取时间和液料比3个因素进行Box-Benhnken中心组合设计,以总生物碱含量和浸膏率的综合评分为响应值,利用响应曲面法对其提取工艺参数进行优化。结果:优选出的伊贝母总生物碱最佳提取工艺为加43.14倍p H 2的69.78%乙醇提取1次,每次1.86 h,考虑到生产实际操作,故将实验条件确定为加40倍p H 2的70%乙醇提取1次,每次1.5 h。在此条件下,伊贝母总生物碱含量达到11.04%,浸膏率达到13.75%,综合评分为98.90。结论:实测值与响应曲面法回归模型的预测值相近,与模型拟合良好,优化的提取工艺准确可靠,具有一定的实用价值,可用于伊贝母总生物碱的提取工艺。     

注射用高纯度蛋黄卵磷脂制备新工艺的研究

本文探索建立了一条以新鲜蛋黄为原料,以乙醇为唯一提取溶剂,制备高纯度注射用蛋黄卵磷脂的新工艺。首先,用4倍重量的96%(v/v)乙醇作为沉淀剂将新鲜蛋黄中的蛋白质沉淀为滤饼,得到初级提取液;然后,再用4倍重量的96%(v/v)乙醇对滤饼抽提3次,提取残余卵磷脂,得到次级提取液。合并提取液,置9℃下静置分层,除去大部分蛋黄油。所得上清液上硅胶柱,用86%(v/v)的乙醇作为洗脱剂,纯化蛋黄卵磷脂,经高效液相色谱检测纯度达98%。并对提取过程进行了优化,得到最佳工艺条件:35℃的96%乙醇溶液,添加量为1∶4(w/w)提取蛋黄液,180 rpm转速下搅拌10 min。抽滤后,用60℃的96%乙醇提取滤饼3次,料液比为1∶4,静置15 min。最佳工艺条件下,蛋黄卵磷脂的提取率可达93.38%。     

喜树叶中生物碱成分提取工艺优化及抗菌抗氧化活性研究北大核心CSCD

运用响应面法优化喜树叶中总生物碱提取工艺并考察总生物碱提取物的抗菌及抗氧化活性。本文在单因素试验基础上,选定超声提取时间为40 min,并进一步选取料液比、超声功率、甲醇比例为自变量,以总生物碱提取率为响应值,利用Box-Benhnken中心组合设计3因素3水平试验,确定最佳提取工艺条件为:超声时间40 min,甲醇:甲酸:水=17. 5∶1∶1. 5,料液比1∶22 g/m L,超声功率240 W。在此条件下,生物碱的得率为1. 67±0. 08 mg/g。抗菌结果表明喜树叶总生物碱提取物(LAE)对S. aureus、E. coli和P. aeruginosa MIC值分别为4. 38,8. 75,8. 75μg/m L。LAE的总抗氧化能力较好,其FRAP值为0. 16±0. 01 mmol·L-1,对DPPH和ABTS自由基清除半抑制浓度分别为4μg/m L和3μg/m L。本研究为喜树次生代谢产物的进一步开发利用提供了参考依据。     

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.