香栓菌多糖的研究

由香栓菌Trametes Suareclens(L.)Fr提取水溶性多糖,经甲醇分级与DEAE——纤维素柱层析,获香栓菌葡聚糖,平均分子量为50000。该葡聚糖经酶试验、高碘酸氧化、红外光谱、Smith降解、乙酰化产物质谱分析,证明为多枝结构。主链由β(1→3)-D-葡萄糖组成,侧链由β(1→6)键连接。     

灵芝多糖的抗癌构效关系及其抗癌作用机制

灵芝多糖是灵芝的主要抗癌活性成分,但灵芝多糖的抗癌构效关系和抗癌机制仍不明了。现有的研究表明,具有抗癌活性的灵芝多糖大多是β-(1→3)-D-葡聚糖。β-葡聚糖中分支度高的有较高的活性,分子量高的也较分子量小的活性大。但新近的一些研究发现,含有其它结构的灵芝多糖和某些小分子量的灵芝多糖也具有免疫调节和抗癌活性。因此,这些灵芝多糖在灵芝抗癌中的作用不可忽视。灵芝多糖的抗癌作用机制目前尚不明了。现已知通过免疫介导作用发挥抗癌作用是灵芝多糖抗癌的主要机制之一。新近的研究发现,膜Ig和TLR-4为灵芝多糖激活机体B细胞的免疫受体,TLR-4也与灵芝多糖激活机体巨噬细胞有关。此外,灵芝多糖抗癌的可能机制还包括活化促分裂原活化蛋白(MAP)激酶,以及抑制肿瘤血管新生等。     

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。     

两种灵芝孢子粉多糖的分离纯化和结构

本文采用水提醇沉法从灵芝孢子粉中提取其粗多糖,经Sepharose CL-6B凝胶柱层析分离得两种主要成分LBPI和LBPII,经高效液相色谱鉴定,均为高均一性成分,分子量分别为9.17×10 ⁴和1.86×10 ⁴;经酸水解、乙酰化和气相色谱分析,确定LBPI的单糖组成为甘露糖、半乳糖和葡萄糖,LBPII的单糖组成为鼠李糖、甘露糖、半乳糖和葡萄糖;通过高碘酸氧化、甲基化和GC-MS进行结构分析,确定LBPI中葡萄糖残基连接方式为1→、1→4,6和1→3,6连接,半乳糖残基为1→6连接,甘露糖残基为1→3,6连接,LBPII中鼠李糖残基连接方式为1→连接,葡萄糖残基为1→、1→4、1→6、1→4,6和1→3,6连接,半乳糖残基为1→6连接,甘露糖残基为1→2,3,6连接。综上,两种多糖LBPI和LBPII均为多分支的中型杂多糖,但两者的单糖组成和连接方式存在差异,这两种多糖成分均为首次报道,可望为灵芝孢子粉的成分、活性研究和资源开发提供理论依据。     

灵芝菌丝液体深层发酵产β-葡聚糖的培养基优化

灵芝β-葡聚糖是灵芝多糖中生物活性较高的一类多糖。通过单因素试验确定影响灵芝液体发酵β-葡聚糖的3个关键参数为:可溶性淀粉(A)40g/L,蛋白胨(B)8g/L,K2HPO4(C)1.5g/L。在此基础上,采用Box-Behnken设计及响应面分析法对各参数及其交互作用进行了研究。结果显示,3因素及AB、AC的交互作用对β-葡聚糖得率的影响均为极显著水平(P0.01)。建立的预测灵芝β-葡聚糖发酵的多项式模型为:Yβ-葡聚糖=8.68+0.22A-0.13B+0.096C+0.13AB+0.16AC+0.045BC-1.17A2-0.81B2-1.06C2。经响应面最优分析,获得3个关键因素的最佳水平为:可溶性淀粉40.47g/L,蛋白胨7.86g/L,K2HPO4 1.53g/L,在该条件下,灵芝菌体β-葡聚糖得率可达8.68mg/g。     

外源物质对灵芝多糖和β-葡聚糖发酵的影响

研究了14种外源物质（化合物）对灵芝细胞生长和发酵合成多糖和β-葡聚糖的影响。结果表明,连翘水提物（3g/L）对灵芝细胞生长具有显著促进作用;薏苡仁酯（3g/L）对灵芝胞内多糖和β-葡聚糖的合成均具有促进作用;而桔梗水提物、硝酸铈铵、硝酸镨、茉莉酸甲酯和硝普钠对灵芝细胞生长和产物合成均具有抑制作用。进一步通过Box-Behnken试验设计和响应面法分析,建立了添加薏苡仁酯发酵产β-葡聚糖的二次多项式模型,经分析得到产β-葡聚糖的最优条件为：薏苡仁酯添加量10.5g/L、接种量16%、添加时间第88小时、发酵初始pH 7.00。在此条件下获得β-葡聚糖的产量可达(40.67±8.43)mg/L,与未添加薏苡仁酯的对照组相比,提高了41.86%;多糖产量为(0.99±0.21)g/L,与对照组相比,提高了31.99%。结果提示所得添加薏苡仁酯的优化条件可定向诱导灵芝β-葡聚糖的合成,同时也表明在灵芝液体发酵体系中添加薏苡仁酯发酵产多糖和β-葡聚糖具有一定的实用价值。     

乙醇-酶体系预处理结合水提法提取灵芝中β-葡聚糖的研究

采用乙醇-酶预处理体系,结合水提法较系统地研究了灵芝子实体中β-葡聚糖的提取技术。结果表明,乙醇-酶体系预处理的关键参数为:乙醇质量分数60%(V/V),加酶量1.5%(M/V,g/m L)、酶解温度45℃、酶解p H8.0;在乙醇-酶体系预处理的基础上,进一步采用单因素试验和Box-Benhnken试验设计与响应面分析法对灵芝子实体中β-葡聚糖的热水提取工艺进行了优化。结果显示水提温度、提取时间、水料比3个因素及水提温度与水料比二者的交互作用对β-葡聚糖的提取有显著影响。经优化后获得3个核心因素的最佳水平为:提取温度80℃、提取时间2.5h、水料比35:1。在乙醇-酶预处理结合水提取条件下,灵芝子实体中β-葡聚糖的提取得率可达0.412mg/g,是传统无水乙醇回流预处理结合水提法提取β-葡聚糖得率的2.1倍。本研究为灵芝β-葡聚糖的进一步提取放大试验奠定了技术基础。     

灵芝菌丝体中β-葡聚糖的提取

比较了热水回流法、热水-酶回流法、超声波法以及超声波-酶水解法等4种提取方法对灵芝菌丝体中β-葡聚糖提取得率的影响。结果表明,采用超声波-酶水解法所得β-葡聚糖的得率最大,影响提取的关键因素为超声波功率(A),水料比(B),p H(C)和加酶量(D)。进一步采用Box-Behnken设计及响应面分析法对这4个因素进行了优化。结果显示,因素A、B、C对β-葡聚糖提取得率的影响达到极显著水平(P0.01),但因素D和所有因素之间的交互作用并不显著(P0.05)。通过回归拟合,建立了预测灵芝β-葡聚糖提取的多项式模型。经响应面最优分析,获得4个因素的最佳水平为:超声波功率275.54W,水料比25.62:1(V/M,m L/g),p H 7.17,加酶量1.05%。经实际试验验证,在该条件下,灵芝菌丝体β-葡聚糖得率可达5.50mg/g。     

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。     

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。     

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.