成熟欧李果肉中单宁提取条件的优化

以成熟欧李为试验材料,乙醇、丙酮、二甲基甲酰胺为提取剂,采用L25（5^6）正交试验设计,从溶剂浓度、固液比、浸提时间、浸提温度等因素的不同水平对欧李果肉中单宁的提取条件进行了研究,结果表明：从欧李果肉中提取单宁的最佳条件为：以丙酮作提取剂,浓度60％,浸提时间4h,浸提温度30℃,固液比1：20;以乙醇作提取剂,浓度30％,浸提时间4h,浸提温度60℃,固液比1：30。     

双水相同时提取次烟叶中茄尼醇和烟碱的研究

研究新型双水相体系同时从次等烟丝中提取茄尼醇和烟碱的可行性和工艺条件。新型双水相体系为丙酮-磷酸氢二钾双水相体系,主要研究了丙酮与水不同体积比、磷酸氢二钾的加入量、料液比、浸提温度、浸提时间、双水相体系pH值对茄尼醇和烟碱得率的影响,确定了最佳提取条件:丙酮与水的体积为5∶5,磷酸氢二钾的加入量为3.0 g,料液比为0.025 g/mL(0.5 g/20.0 mL),浸提温度为50℃,浸提时间为4 h,pH值为10。     

烟草废料中绿原酸的提取工艺研究

讨论了从烟草废料中提取绿原酸的优势和甲醇、乙醇、丙酮、水等不同溶剂经超声波辅助提取绿原酸的效果：研究结果表明,用体积分数40％的甲醇得到的浸提液中,绿原酸质量浓度为2．11mg／mL,比以水为溶剂时高出近50％.不同浓度的甲醇溶液中,体积分数50％的甲醇提取绿原酸的浓度最高。对树脂的吸附动力学分析表明,大孔树脂CN-101对烟草浸提液中绿原酸的吸附遵循Freundlich等温方程,吸附和解析分离所得的绿原酸收率为87．6％.在超声辅助条件下,利用甲醇等有机溶剂提取烟草中的绿原酸,进而用大孔树脂进行吸附分离的方法可行。     

十二烷基硫酸钠辅助提取布渣叶中的黄酮类物质

以布渣叶为研究体系,采用表面活性剂辅助热回流法提取黄酮类物质.考察了表面活性剂种类及浓度、提取时间、液固比和溶剂pH等因素,并通过实验数据进行了正交试验设计,得到最优的工艺条件:表面活性剂选择十二烷基硫酸钠(SDS),质量浓度0.8 g/L,提取时间105 min,液固比45 mL/g,溶剂pH 6.3.在此条件下,布渣叶黄酮得率为15.73％,与其他方法相比具有显著优势.     

水皂角多酚的提取工艺研究

本研究通过单因素实验和正交实验 ,以提取物中水皂角总多酚含量为考察指标 ,对影响水皂角多酚提取效果的各因素进行了研究。结果表明各因素对水皂角多酚提取效果的影响程度从高到低依次为 :浸提温度 >乙醇浓度 >固液比 >浸提时间。确定了水皂角多酚的最佳提取工艺为乙醇浓度 70 % ,浸提温度 70℃ ,浸提时间 5h ,固液比 1∶10。     

苦瓜中苦瓜甾苷的提取工艺研究

本研究通过单因素实验和正交实验,采用HPTLC检测方法,以苦瓜甾苷浸提量为考察指标,对影响苦瓜甾苷提取效果的各因素进行了研究。结果表明各因素对苦瓜甾苷提取效果的影响程度从高到低依次为:乙醇浓度>固液比>浸提时间>浸提温度。确定了苦瓜甾苷的最佳提取工艺参数为乙醇浓度80%,浸提温度55℃,浸提时间5h,固液比1:10。     

单宁酸沉淀法提取废烟叶中的烟碱

以单宁酸为沉淀剂,用超声辅助提取法提取废次烟叶中的烟碱。考查了提取介质、固液比、提取时间和提取温度及沉淀剂用量等对烟碱提取率的影响。实验结果表明：用水做提取介质,在固液比为1∶15（g/mL）,70℃温度下超声提取30 min,用4.5g单宁酸进行沉淀,烟碱的提取率为1.06%。     

乙醇浸提法提取大枣芦丁及其抗氧化性的研究

以大枣为原料,采用乙醇浸提法提取芦丁,以芦丁得率为评价指标,通过正交试验优化影响大枣芦丁得率的若干因素:液料比、乙醇浓度、浸提时间、浸提温度,确定其最佳工艺条件为液料比20∶1(mL∶g)、乙醇浓度60%、浸提时间3.0 h、浸提温度70℃,此条件下大枣芦丁得率为2.16%;大枣芦丁粗提物中芦丁含量为8.57%。对芦丁进行体外抗氧化能力测定结果表明,大枣芦丁具有一定的清除DPPH自由基的能力,5μg/mL的大枣芦丁对DPPH自由基的清除率可达到58.80%,25μg/mL的芦丁对OH自由基的清除率达49.80%,本研究对芦丁资源的进一步开发利用提供参考。     

菊芋块茎浸提液对生菜种子萌发生长的化感作用

以新鲜菊芋块茎、烘干菊芋块茎全粉和菊粉的水浸液作为化感物质,以发芽率、芽长、根长、超氧化物歧化酶(SOD)、丙二醛(MDA)、可溶性蛋白作为种子萌发和幼苗生长的指标,探讨不同菊芋块茎浸提液对生菜种子萌发生长的化感作用。结果表明:当菊粉溶液浓度为40 mg·mL~(-1)(T4)时,发芽率最高,比对照高20.1%;当干样浸提液浓度为5 mg·mL~(-1)(T1)时,发芽率比对照高9.6%;当干样浸提液浓度为40 mg·mL~(-1)(T4)时,对生菜种苗芽长促进作用最明显,比对照高9.2%,在干样浸提液浓度为5 mg·mL~(-1)(T1)时,根长最长,比对照高28.3%;当菊芋块茎鲜样浸提液浓度为20 mg·mL~(-1)(T3)时,SOD的活性达到最高,而MDA含量低于对照,说明菊芋鲜样浸提液可以有效提高生菜的抗逆性;当菊粉溶液浓度为5 mg·mL~(-1)(T1)和10 mg·mL~(-1)(T2)时,MDA含量和蛋白含量极低,显著低于对照。采用化感综合效应指数分析菊芋块茎浸提液对生菜种子萌发的影响,结果表明,块茎鲜样和干样浸提液对生菜的种子萌发具有明显促进作用,而菊粉溶液具有较强的抑制作用。在实际生产中,应根据不同的生长要求,使用不同浓度的浸提液,以达到最佳的促进效果。研究表明,菊芋全粉可以更有效地作为化感物质,促进生菜种子萌发和幼苗生长。     

无花果果皮中花青素的提取工艺的建立

本研究使用单因素方法考察了无花果(Ficus carica L.)果皮中花青素的最佳提取条件,并考察了7种参数对花青素提取率的影响。参数设置如下:溶剂性质(水,甲醇,乙醇和丙酮)、提取次数(1~3次)、固液比(1/50,1/100,1/150和1/200)、提取时间(60 min,120 min,180 min和240 min)、甲醇浓度(0,20%,40%,60%,80%和100%)、酸类型(盐酸,乙酸,柠檬酸和酒石酸)和酸浓度(0,1%,2%,5%和10%)。使用pH-示差法测量无花果果皮中单体花色素的含量。研究显示,无花果果皮中花青素的最佳提取条件为:溶剂为甲醇溶剂,提取次数为2次,固液比为1/100,提取时间为180 min,甲醇浓度为80%,酸类型为柠檬酸,柠檬酸浓度为5%。该最佳提取条件下的花青素的提取率达到最高(345.62 mg/100g DS)。     

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.