大孔树脂吸附分离烟草绿原酸的研究

通过比较8种大孔吸附树脂对烟草绿原酸的吸附分离性能,筛选出适合分离烟草绿原酸的树脂,并对其动态吸附特性进行研究.结果表明,XDA-1树脂对烟草绿原酸不仅吸附量大,而且解吸率高,适合烟草绿原酸的分离富集.该树脂吸附分离烟草绿原酸的工艺参数为:上柱液浓度3.5 mg/mL,pH 3.0,流速3倍柱床体积/h;以6倍柱床体积的40%乙醇进行洗脱,解吸附效果最佳,绿原酸总回收率为80.06%,初步吸附分离得到的产品中绿原酸含量为39.20 g/100 g.     

大孔树脂分离纯化辣椒叶总黄酮的工艺研究

目的:筛选适合分离纯化辣椒叶总黄酮的一种大孔树脂,同时用响应面法进行优化得到最佳纯化工艺。方法:采用热回流法提取辣椒叶总黄酮,以吸附率和解吸率为考察指标,考察6种不同型号的大孔树脂(HPD100、HPD450、HPD600、HPD826、D101、AB-8)对辣椒叶总黄酮的吸附能力与解吸能力,确定最佳树脂。通过动态吸附解吸实验考察此树脂对辣椒叶总黄酮的最佳分离纯化工艺。结果:通过对辣椒叶总黄酮吸附分离性能的分析显示HPD600为最佳树脂,最优工艺为:上样浓度为10 mg/mL,上样量为10 mL,洗脱体积为4 BV,洗脱液流速为4 mL/min,洗脱液pH为7,依次用水、10%、30%乙醇冲洗树脂柱,50%乙醇为洗脱液。纯化后的黄酮纯度435.4 mg/g。结论:该方法简便,操作简单,对辣椒叶总黄酮的纯化效果较好。     

桑椹中黄酮类物质的大孔树脂纯化工艺

以桑椹中黄酮类物质的吸附量和解吸率为指标,对比分析HZ-801、HZ-816、HZ-818等12种大孔吸附树脂对桑椹提取液的分离纯化效果,优选出最佳树脂HZ-801并通过对上样液pH、上样液质量浓度、上样量、吸附流速、洗脱剂质量浓度、洗脱剂用量、洗脱流速等影响因素的考察,确定最优工艺:吸附阶段上样液pH=4,上样液质量浓度0.45mg/mL,上样量420mL,吸附流速120mL/h,动态吸附量(干树脂)25.34mg/g,吸附率84.25%;洗脱阶段的洗脱剂体积分数为60%乙醇,洗脱剂用量270mL,洗脱流速120mL/h。此优化工艺条件下的洗脱率为85.78%,总黄酮纯度从23.64%提高到82.36%。     

大孔吸附树脂提取7-木糖-10-去乙酰紫杉醇酶解产物10-去乙酰紫杉醇

本研究利用大孔树脂富集7-木糖10-去乙酰紫杉醇的酶解产物10-去乙酰紫杉醇.首先以10-去乙酰紫杉醇(10-DAT)绝对含量为指标,通过HPLC测定比较HP20、XAD4、XAD16、XAD1600四种大孔树脂对10-去乙酰紫杉醇的吸附与解吸性能力,筛选出最佳树脂XAD1600进行实验.最佳的吸附解吸条件为:树脂柱高径比10:1,吸附流速20 mL/min,吸附量23.85 mg/mL,以6倍柱床体积的90%乙醇为洗脱液,洗脱流速20 mL/min.经XAD1600型树脂富集后10-去乙酰紫杉醇回收率达96.5%,含量20.5%.且树脂柱重复使用3次后,其吸附能力仅降低5%.     

从火棘果中提取精氨酸的研究

以天然野生植物火棘果为原料分离提取精氨酸,考察了树脂类型、吸附方式、温度、pH值、洗脱液、脱色及精制方法等因素对提取精氨酸的影响,并对产物进行了分析鉴定。结果表明,在20℃、pH值7-8的条件下,选用D001型大孔阳离子交换树脂静态吸附,40 min即达到饱和;以3 mol.L-1氨水为洗脱液,流速控制在40 mL.h-1,精氨酸的洗脱率达到90%以上;采用711型阴离子树脂进行脱色,D001型大孔阳离子交换树脂动态精制,精氨酸的提取率达到95.83%。     

大孔吸附树脂AB-8和十八烷基硅胶色谱分离纯化蛹虫草发酵液中虫草素工艺研究

主要研究了从蛹虫草发酵液中提取虫草素的工艺,确定了大孔吸附树脂AB-8及十八烷基键合硅胶反相层析柱对蛹虫草发酵液中虫草素的分离条件;吸附最佳工艺条件为上样液p H6,上样浓度0.4mg/m L,上样量5BV,吸附流速1.0BV/h;解吸最佳工艺条件包括解吸液20%乙醇,解吸体积15BV,解吸流速4BV/h。得到的解吸液进一步以十八烷基键合硅胶分离,条件为上样液p H6,梯度洗脱,流动相为p H6的水和p H6的乙醇。洗脱液通过结晶和重结晶得到精制虫草素。三步得到的虫草素纯度分别达到40%、90%和99%以上。     

超声辅助提取野生与人工栽培黑果枸杞花色苷含量研究

黑果枸杞含有的花色苷类成分对人类健康有着重要意义。为探究野生与人工种植黑果枸杞花色苷含量差异,本实验利用超声辅助回流提取,通过单因素实验和Box-Benhnken实验设计优化提取条件,得到最佳提取条件为:提取时间25.62 min、提取温度48.67℃、乙醇浓度84.35%、料液比1∶20 g·m L-1。在此条件下测得野生、人工种植黑果枸杞花色苷平均含量分别为6.141 mg/g、16.014 mg/g。本实验结果为黑果枸杞种植及利用提供了重要依据。     

聚酰胺树脂精制青钱柳黄酮的研究

研究青钱柳黄酮的最佳精制工艺.通过不同条件下聚酰胺树脂对青钱柳黄酮的静态和动态吸附与解吸特性的研究,确定聚酰胺树脂对青钱柳黄酮的最佳精制工艺;采用优选出的最佳精制工艺对青钱柳黄酮粗提物进行多次精制,得到高纯度青钱柳黄酮.聚酰胺树脂精制的最佳条件是:在室温和吸附液为碱性,吸附流速为2.0 mL/min时吸附能力最强;在室温和解吸流速为2.0 mL/min时,以40%乙醇洗脱效果最好;青钱柳黄酮粗提物经过聚酰胺树脂三次吸附和解吸后黄酮含量由粗品的11.40%提高到了81.34%,纯度提高了6.14倍.聚酰胺树脂对青钱柳黄酮纯化效果好,总黄酮含量高,产品安全.     

大孔吸附树脂分离纯化培养基残基中虫草素

采用大孔吸附树脂分离纯化人工蛹虫草培养基残基中的虫草素,以HPLC法测定样品中虫草素含量,筛选出了适宜的大孔树脂NKA-II。研究了pH、洗脱剂乙醇体积分数等因素对该树脂吸附性能及解析性能的影响。结果表明,NKA-II型树脂纯化虫草素的最佳吸附条件为pH9,吸附流速2BV/h,该树脂对虫草素的吸附量可达到16.5mg/g。洗脱工艺条件为2.5倍树脂柱体积的50%乙醇,NKA-II大孔树脂对虫草素的解析率可达到95%以上。     

大孔树脂分离纯化“黑金刚”紫马铃薯花青苷工艺研究

以紫色马铃薯"黑金刚"花青苷为原料,采用D101、HDP100A、HDP450A、NK-9、AB-8五种大孔吸附树脂对花青苷的吸附与解析特性进行了比较研究,并在此基础上,采用最佳大孔树脂对花青苷纯化过程中的静态、动态吸附和解析附条件进行了优化研究。结果表明AB-8大孔树脂具有较好的吸附和解析能力,是纯化紫色马铃薯花青苷的最佳树脂,较优纯化条件为:上样液花青苷浓度为0.028mg.g-1,上样液pH=2,洗脱液乙醇浓度为50%,洗脱液pH=1,吸附流速为1mL.min-1,洗脱流速为1mL.min-1。经大孔树脂纯化后,色价值比纯化前提高了7.55倍。     

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.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

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.