裂褶菌胞内多糖的分离纯化鉴定及其性质

裂褶菌菌丝体用热水提取,乙醇沉淀,Sevag法脱蛋白,逆向流水透析,得胞内多糖粗品,经Sephadex A-50、Sephadex G-200柱层析纯化,得胞内多糖纯品,称SPG。纯度经纸层析、Sephadex G-200柱层析、高效液相色谱分析、聚丙烯酰胺凝胶电泳测定,结果表明SPG为单一均匀组分。 SPG水解物经纸层析、薄层层析分析证实它是由葡萄糖组成的一种葡聚糖结构,SPG的部分水解、酶解、红外光谱、核磁共振氢谱分析表明具有β(1→3),β(1→6)糖苷键。凝胶过滤法测定SPG的分子量约为10万。     

紫球藻多糖化学结构解析

为明确紫球藻多糖的化学结构,本文采用化学分析和光谱分析方法对紫球藻多糖的一级糖链结构进行了分析。GC分析表明该多糖由木糖、葡萄糖和半乳糖组成,为一种杂多糖,其摩尔比为:2.96∶1.25∶3.06;红外光谱分析结果显示紫球藻多糖为硫酸化多糖,糖苷键类型为β构型;化学分析结果推断紫球藻多糖糖链连接方式以1→3为主,存在少量1→2,1→4,1→6键型,且半乳糖在支链或主链末端有较大量的存在,木糖和葡萄糖在主链或靠近主链区域有特定分布;NMR分析显示紫球藻多糖的硫酸酯基连在C-6上,且多糖的糖苷键为β型;GC-MS联机分析进一步确定紫球藻多糖为一种主要含有1→3糖苷键,并含有1→4,1→6糖苷键的杂多糖。综合上述分析,推断出紫球藻多糖的糖链主链的重复单元结构。     

松杉灵芝发酵菌丝体中水溶多糖的分离纯化与结构的比较研究

松杉灵芝发酵菌丝体经热水提取,冻融分级及乙醇二次分级,分离纯化出GFb级份,电泳及凝胶柱层析示其为均一多糖,分子量为9.8万。小于子实体多糖相应级份。 GFb经红外光谱,气相色谱,气质联机,碳13核磁共振,高碘酸盐氧化,Smith降解,甲基化及部分酸水解分析,确定其基本结构中主链为1→6葡萄糖基和1→6半乳糖基构戍,二者之比为1∶1,分支点在0-3位上,分枝点率为50％,与子实体多糖GF_3相同,侧链由1→3葡萄糖基,1→4葡萄糖基,末端葡萄糖基及末端半乳糖基构成,分子中分枝率为55.6％,较子实体多糖GF_3分枝率略低,分枝链略短。     

大马勃水溶性多糖的结构研究

采用热水浸提,乙醇沉淀的方法得到大马勃粗多糖,经Sevag法脱蛋白,DEAE—sepharose fast flow离子交换层析及sephacrylS-300HR凝胶过滤法得大马勃多糖（CGPI-1）。气相色谱研究表明,其单糖组成为：Gal,Glc,Man等四种单糖,其中Gal,Glc,Man,摩尔比为3．92：11．28：1．22。经部分酸水解,红外光谱及核磁共振光谱,高碘酸氧化,Smith降解等分析,CGPI-1的主链由Man和Glc构成,存在β型和α型两种糖苷键构型,支链或主链的末端残基由β-Gal（1→4）,β-Glc（1→6）,α—Glc（1→4）构成,其分子中存在酰胺结构。原子力显微镜观察发现CGPI-1呈分支的线性分子,在水溶液中容易互相缠绕形成强大的网络结构。     

长松萝多糖的研究

长松萝经三氯甲烷抽提后风干,用热水提取,乙醇沉淀,经微晶纤维素柱层析纯化,得白色粉末状多糖USL。USL经Sephadex G-150柱层析证明为一组均匀多糖,其糖的含量为89.52％。经气相色谱检定,由阿拉伯糖(Ara)、木糖(Xy1)、甘露糖(Man)、葡萄糖(Glc)聚合而成,其克分子比为0.31:0.05:1.00:18.10。经Sephadex G-200柱层析测定,平均分子量为30×10~4,经高碘酸氧化,Smith降解,有甲酸、丙三醇、赤藓醇生成。红外光谱在896cm-~1处有吸收,证明USL多糖结构主要以β(1→4)、β(1→6)甙键连接而成的杂多糖。     

超声提取的麦冬多糖POJ-U1b的结构分析及AFM观测

本文利用超声提取麦冬多糖,经DEAE-52纤维素柱层析进行分离纯化,利用Sephadex G-150凝胶柱层析对得到的多糖组分POJ-U1b进行纯度鉴定,结果显示POJ-U1b为单一组分。利用气相色谱法、红外光谱法及核磁共振对POJ-U1b的结构进行了研究,利用原子力显微镜对不同浓度的POJ-U1b表面形貌进行了观测。结果显示,麦冬多糖POJ-U1b是由葡萄糖组成的葡聚糖,具有糖类物质的特征吸收峰,其糖环构型既有吡喃型又有呋喃型,糖链主要由→6)-α-D-Glcp(1→连接方式构成。AFM观测结果表明POJ-U1b具有高度分支的化学结构,糖链间通过糖单元间不同的链接方式衍生出许多环状和分支结构。随着多糖浓度的增大,POJ-U1b呈现出链状及片状粘连结构,这种现象可能与糖链间的范德瓦尔斯相互作用及糖链间氢键缔合有关。     

灵芝孢子粉水溶性多糖的分离、纯化及结构研究

灵芝孢子粉的热水提取液经醇析,脱脂,去单寡糖后由SepharoseCL 6B柱层析纯化,所得多糖SGL Ⅱ2经高效液相方法鉴定纯度为单一级分,相对分子质量为5 .37×10 4。再经部分酸水解、高碘酸氧化、Smith降解、甲基化分析及IR、GC、GC MS和13 CNMR等方法确定其结构。结果表明多糖SGL Ⅱ 2由葡萄糖和半乳糖组成,为少分支结构,由1→3连接和1→6连接的葡萄糖构成主链,部分1→6连接葡萄糖在3位或4位有分支,侧链为1→4连接的半乳糖,分支末端残基为葡萄糖。     

山豆根多糖的研究

从山豆根沸水提取物中用 DEAE- Cellulose离子交换柱层析及 Sephadex G- 1 0 0凝胶层析分离纯化得—水溶性多糖 SSP1,SSP1用 TFA全水解的产物经 PL C及 GC分析证明仅含葡萄糖 ,平均分子量为 2 .2 4× 1 0 4 ,比旋光 [α]2 0D=+ 68°( c 0 .75,H2 O) ,经高碘酸氧化、Smith降解、甲基化分析、红外光谱、1H及 13C NMR分析证明其化学结构为以α( 1→ 4)葡聚糖为主链 ,并且每 1 2个主链单元分别在 3- O及 6- O位有分枝的葡聚糖     

铁皮石斛原球茎多糖DCPP1a-1的理化性质及抗肿瘤活性

铁皮石斛原球茎粗多糖(DCPP)经阴离子交换纤维素柱(DEAE-52)和凝胶柱(Sephadex G-200)色谱分离纯化,得灰色粉末状多糖DCPP1 a-1。采用薄层层析、高效液相色谱、紫外光谱、红外光谱和高碘酸钠氧化等方法进行组成结构分析;并研究了DCPP1 a-1的体内抗肿瘤作用。结果表明,DCPP1 a-1为均一组分,具有α-吡喃糖苷键,分子中1→6键、1→2/1→4键、1→3键所占的比例分别为4.0%,52.1%和44.9%,平均分子量为189kD,由甘露糖和葡萄糖按7.015∶1的摩尔比组成,是首次从原球茎中分离出的新型多糖。多糖DCPP1 a-1的三个剂量组50、150、250 mg/kg对H22肝癌小鼠有不同程度的抑瘤作用,抑瘤率分别为28.6%、19.3%和15.7%。其中以低剂量组的抑瘤效果最好(P<0.05),并显著提高了胸腺和脾指数(P<0.05)。     

灰树花多糖PGF-2的理化性质及化学结构的初步表征

本文利用仪器分析技术对灰树花多糖级分PGF-2的理化性质和化学结构进行了研究。灰树花粗多糖PGF经DEAE—Sephadex A-25柱层析分离得到一种多糖级分为糖蛋白质缀合物PGF-2,其多糖含量95.4%,纸层析及Sephadex G-200凝胶柱层析证实PGF-2为均一多糖;凝胶渗透色谱测定其数均分子量Mn为118 803 Dal,重均分子量Mw为119 612 Dal;经气相色谱分析PGF-2的糖基由葡萄糖、甘露糖和半乳糖组成,摩尔比为1:2.35:1.22;氨基酸分析结果表明PGF-2的蛋白质由16种氨基酸组成。红外光谱与核磁共振谱证实PGF-2主要存在α型糖苷键。由β-消除反应推断PGF-2中多糖与氨基酸的连接方式以-O-Ser连接。     

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.