柿子多糖的分离纯化和结构分析

利用水提醇沉提取柿子多糖(WPP),经季铵盐沉淀法和凝胶柱层析对柿子粗多糖进行分离纯化,得到了水溶性的柿子粗多糖(WPP1)和盐溶性的柿子粗多糖(WPP2)两个柿子多糖组分。通过对理化性质、分子量和单糖组成测定结果分析,确定WPP1是含有α糖苷键的化合物,由L-鼠李糖、L-阿拉伯糖、D-葡萄糖和D-半乳糖四种单糖组成,四种单糖的摩尔比为0.8831∶0.6862∶0.7022∶1,分子量为2.05×105Da。WPP2由L-阿拉伯糖和D-半乳糖两种单糖组成,其摩尔比为0.8466∶1,分子量为2.63×105Da。WPP1和WPP2均表现出吡喃糖的特征吸收。     

芦荟多糖的分离纯化及性质研究

采用水提醇沉法提取芦荟多糖,经DEAE-C32柱层析分离,Sephades G-100进一步纯化,得AⅠ、AⅡ和AⅢ三种芦荟多糖。Sephadex G-100凝胶色谱表明,AⅠ组分为均一组分,其分子量约为3.8×10~4。借助气相色谱技术,研究了芦荟粗多糖和AⅠ组分的单糖组成。另外,红外光谱鉴定芦荟多糖主要为吡喃多糖。     

荔枝壳多糖特性研究

多糖是荔枝壳的重要活性成分,本研究采用阴离子交换柱和凝胶过滤柱对荔枝壳多糖进行分离纯化。凝胶渗透色谱测定其分子量为14000 Dal。通过气相色谱测定其单糖组成为甘露糖、半乳糖和少量的阿拉伯糖,分子链由1,2键、1,3键和1,6键组成,不含1,4键。红外光谱分析表明甘露糖以β-D-甘露糖形式存在,不含羧基基团。     

猪肚菇多糖WPG1的相对分子质量测定及原子力显微镜观测

热水提取猪肚菇粗多糖中的酸性多糖WPG1,经凝胶纯化后用高效液相色谱（HPLC）测定其相对分子质量,用气相色谱对其单糖组成进行分析,用原子力显微镜（AFM）对其形态结构进行观测。结果表明：酸性多糖WPG1经SephacrylS-300凝胶层析纯化后得到WPG1-1和WPG1-2这2个组分; 经HPLC分析可知WPG1-1与WPG1-2均为单一组分,其相对分子质量分别为1.7×106和1.6×104; WPG1-1与WPG1-2的单糖组成主要是糖醛酸、甘露糖、葡萄糖和半乳糖; 原子力显微镜观测图分析表明WPG1-1为网链状聚集体结构,WPG1-2呈梭状聚集体,两者均非单链存在。     

一种水溶性党参多糖的分离纯化及结构分析

采用水提醇沉法得到党参粗多糖(COP),采用Sevag法除去蛋白成份,接着通过Sephacry1 S-200HR及Sephadex G-25凝胶柱色谱分离得到均一多糖COP-1。凝胶渗透色谱法(HPGPC)测定其纯度和平均分子量。高效液相色谱法(HPLC)确定其单糖的组成。红外光谱及核磁推测COP-1结构。结果表明COP-1平均分子量约为2.1×10~3 Da,且均由阶D-(2→1)呋喃果糖组成。     

白术多糖WAM-1结构的色谱分析和原子力显微镜观察

通过热水浸提法从草本植物白术根茎提取的水溶性粗多糖,经DEAE-52纤维素柱层析分离和Sephadex G-200凝胶过滤柱层析纯化,得到组分WAM-1.采用高效液相色谱(HPLC)检测WAM-1的纯度,气相色谱(GC)对其单糖组分进行分析,原子力显微镜(AFM)对其分子外貌进行观测.结果显示:WAM-1为均一多糖,由葡萄糖和半乳糖以3.01:1摩尔比构成;在不同浓度溶液条件下,WAM-1分子以不同形态存在,多糖溶液的浓度对WAM-1的分子链构象及链间相互作用形式产生影响,推测可能与WAM-1分子内、分子间的氢键缔合作用有关.多糖浓度为10μg/mL时,可清晰的观察到WAM-1是以刚性链状形态存在,且具有多分支结构.     

苦楝果多糖的分离纯化及组成分析

利用水提醇沉法提取苦楝果实中的多糖,经DEAE-52柱层析分离,得到MP1、MP2和MP3三个多糖组分,用Sephadex G-100凝胶色谱柱对MP1进行纯化鉴定,结果显示为单一峰。借助气质联用仪,对苦楝粗多糖和组分MP1进行了成分分析。红外光谱分析表明苦楝多糖的单糖残基以吡喃环和呋喃环的形式存在。     

苦瓜多糖的提取、分离纯化及组成性质

正交实验确定提取工艺后,用热水提取法得到苦瓜多糖(MCP).对MCP进行DEAE-32离子交换层析分离,得到3个多糖组分MCP1、MCP2和MCP3. 进一步采用Sephacryl S-400凝胶层析进行分离,经凝胶层析和高效液相色谱检测表明,MCP1、MCP2为均一性多糖组分.通过高效液相凝胶色谱法测定了两者的相对分子质量分别为1.16×106和7.45×105.用PMP衍生化法测定其单糖,结果表明: MCP1系由Man、Rham、GlcUA、GalUA、Glu、Gal、Xyl、Ara等单糖组成的杂多糖,摩尔比为1.03:2.93:1.00:14.95:2.16:30.70:2.85:4.50.MCP2系由Rham、GalUA、Gal、Xyl、Ara等单糖组成的杂多糖,对应的摩尔比为1.63:21.88:4.66:1.00:1.29.紫外光谱表明该多糖不含蛋白质和核酸.     

一株胞外多糖产生菌的筛选鉴定及其多糖成分研究

以菌落周围有粘稠分泌物为初筛标准从土壤中筛选胞外多糖产生菌,苯酚-硫酸法测定初筛菌胞外多糖的产量;将胞外多糖产生菌LE-3进行形态学观察、BIOLOG分析与16S rDNA鉴定;提取菌株LE-3胞外粗多糖,该粗多糖经Sevage法除蛋白、透析和CM-琼脂糖凝胶FF、DEAE-琼脂糖凝胶FF、丙烯葡聚糖凝胶S-200HR柱层析进行纯化,傅里叶红外光谱法、薄层层析法和高效液相色谱法分析胞外多糖的单糖组成。结果表明:从土壤中筛出26株符合初筛标准的菌株,3株产糖量在5 g/L以上,其中菌株LE-3产量为5.29 g/L;根据形态学特征、BIOLOG和分子生物学分析,初步鉴定菌株LE-3为一株解淀粉芽孢杆菌亚种(Bacillus amyloliquefaciens subsp.amyloliquefaciens);该菌株胞外粗多糖经Sevage法除蛋白、透析和三次柱层析纯化后,得到单一组分的LE-3胞外多糖;傅里叶红外光谱法、薄层层析法和高效液相色谱法分析确定该多糖为果聚糖。     

薯蔓多糖的分离纯化和性质鉴定

以我国资源量巨大的薯蔓为原料, 采用中试设备, 利用水提醇沉法提取多糖。研究了活性炭脱色工艺, 经初步纯化获得薯蔓多糖(PSPV), 并研究了其理化性质。DEAE-纤维素柱对来自于二个季节的PSPV进行分离、纯化, 分别得到PSPVⅠ和PSPVⅡ、PSPVⅢ三个多糖组分, 高效凝胶过滤色谱法测定三个组分的分子量分别为6.278×104 D, 3.801×104 D和1.418×104 D, 气相色谱结合标样测定单糖组成。研究结果为充分高效利用薯蔓资源提供了理论依据。     

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.