毛头鬼伞多糖对烟草酶活性和同工酶谱的影响

分析了毛头鬼伞(Coprinus comatus)真菌多糖诱导烟草对烟草花叶病毒(TMV)抗性过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、几丁质酶、-β1,3-葡聚糖酶活性的变化。结果表明,毛头鬼伞多糖可提高POD、PPO、PAL、几丁质酶和-β1,3-葡聚糖酶的活性,接种TMV后毛头鬼伞多糖处理的烟草酶活性显著高于不处理者。上述结果提示,毛头鬼伞多糖处理后烟草酶活性的增强可能与其诱导烟草获得抗性有关。     

绞股蓝多糖体外抗氧化活性研究

研究绞股蓝多糖的单糖组成及抗氧化活性.采用气相色谱(GC)分析绞股蓝多糖的单糖组成,通过体外抗氧化评价体系研究绞股蓝粗多糖(GPMPP)和精制多糖(GPMP)的总还原力、清除DPPH自由基、羟自由基的活性以及抗脂质过氧化作用.结果显示,绞股蓝多糖由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖组成,物质的量比为1.39∶3.76∶1.00∶1.64∶4.98∶5.88.绞股蓝多糖具有较好的还原能力,对DPPH自由基和·OH具有较强的清除能力,并且对小鼠肝匀浆自发性脂质过氧化和Fe2+-H2O2诱导的小鼠肝匀浆脂质过氧化具有较好的抑制作用.以上结果表明,绞股蓝多糖具有明显的抗氧化活性.     

旱莲草多糖的提取及其抗氧化活性研究

采用水/甲醇混合溶剂浸泡提取旱莲草的多糖组分,利用硅胶柱层析和中压液相色谱,对多糖进行分离纯化,纯化后的多糖组分经薄层层析分析发现,这些多糖主要组成单糖均为葡萄糖和果糖。旱莲草多糖在总还原能力、总抗氧化能力和FRAP抗氧化能力测试中均显示较好的活性,能够有效清除羟自由基和DPPH自由基,在1.5 mg/m L的浓度下,对羟自由基的清除效率为(12.33~56.81)%,粗多糖组分在1 mg/m L的浓度下对DPPH自由基的清除效率为(17.88~84.47)%,精分多糖组分在5 mg/m L的浓度下,对DPPH自由基的清除效率为(18.64~91.35)%;极性小的多糖抗氧化活性显著优于极性大的多糖,抗氧化活性最高可达后者的11倍之多;粗多糖组分的抗氧化活性一般优于纯化后的相应精多糖组分,这说明旱莲草的不同多糖分子之间可能存在协同抗氧化作用。     

六妹羊肚菌多糖部分理化性质及抗氧化活性研究

分离纯化人工栽培的六妹羊肚菌子实体多糖,对其结构和抗氧化活性进行研究。采用水提醇沉法提取六妹羊肚菌子实体多糖(MSP),采用DE-52纤维素柱和Sephadex G-100进行多糖的分离纯化,借助HPGPC和HPLC测定多糖分子量及单糖组成。通过DPPH自由基、羟自由基和超氧阴离子自由基的清除作用,评估其体外抗氧化活性。构建H_2O_2介导的氧化压力损伤的PC12细胞模型,评估其基于抗氧化的神经保护作用。结果显示,六妹羊肚菌水溶性多糖平均分子量为287 588 Da,单糖组成为甘露糖,葡萄糖和半乳糖,占比约为9∶1∶6。六妹羊肚菌多糖具有优良的自由基清除活性,同时,能够通过重塑SOD、CAT、GSH-Px等抗氧化酶系活性,缓解H_2O_2诱发的氧化压力的细胞损伤,抑制PC12细胞凋亡。涉及通路为Bax/Bcl及Caspase。六妹羊肚菌水溶性多糖具有优良的抗氧化活性,表现出一定的神经保护作用。     

醇沉条件和干燥方式对毛头鬼伞子实体多糖品质的影响

为改善毛头鬼伞子实体多糖的性状,以粗多糖得率、多糖含量、吸潮性及色素含量为指标,对乙醇沉淀制备多糖的参数进行了优化。结果表明:子实体经提取后浓缩至浓缩比为1∶2,即m(物料干质量/g)∶V(提取液/m L)=1∶2时以60%乙醇沉淀,再以60%乙醇洗涤1次,经冷冻干燥所得粗多糖产品多糖含量较高、色浅,且吸潮性降低,性状得到明显改善。     

山楂多糖提取工艺优化及其抗氧化活性研究

目的：优化热水浸提法提取山楂多糖的最佳工艺条件,并研究其结构和体外抗氧化活性。方法：在单因素试验的基础上,以水浴温度、水浴时间、料水比、冷浸时间为因素,通过正交试验设计优化其提取工艺;多糖经纯化后分别采用GPC、GC-MS分析其分子量和单糖组成,并通过对超氧自由、羟自由基、DPPH（1,1-二苯基-2-三硝基苯肼）自由基清除试验测定山楂多糖的抗氧化活性。结果：最佳提取条件为浸提温度90 ℃、浸提时间6 h、料水比1∶20、冷浸时间为13 h,此条件下提取的多糖经过纯化后,其分子量为5.59×104 Da,单糖含量比例（阿拉伯糖∶木糖∶甘露糖∶葡萄糖∶半乳糖）为1∶1∶28∶8∶12。经测定,多糖具有一定的超氧自由基、羟自由基、DPPH自由基体外清除能力,在0.5~2.5 mg/mL的浓度范围内,清除率分别为12.3%~37.9%、12.3%~40.9%、15.3%~42.6%,说明抗氧化活性较好。结论：本研究可为山楂资源的开发利用和山楂多糖的药理研究提供科学依据。     

海藻多糖的单糖组成对体外抗氧化活性的影响

比较广西北部湾石莼(Ulva lactuca L.)、海带(Laminaria japonica)、裙带菜(Undaria pinnatifida Surin-gar)、紫菜(Porphyra)的单糖组成及抗氧化活性的差异,揭示多糖结构与其体外抗氧化活性的关系。利用PMP柱前衍生化HPLC分析海藻多糖的单糖组成,采用羟自由基清除试验、超氧阴离子自由基清除试验及DPPH自由基清除试验指征其体外抗氧化活性,结果表明,4种海藻多糖的单糖组成在主成分空间分布离散,石莼及紫菜主要由葡萄糖组成,海带主要由甘露糖组成,裙带菜则主要由半乳糖组成;其体外抗氧化活性存在显著差异,裙带菜多糖对DPPH的清除能力(半抑制浓度IC₅₀值为0. 56±0. 02 mg/mL)显著高于其他3种海藻多糖;石莼、裙带菜与海带对羟自由基均有较强的清除活性,而紫菜多糖对羟自由基的清除能力较差(IC₅₀值为26. 59±0. 98mg/mL);石莼与裙带菜对超氧阴离子的清除活性较强,显著高于海带与紫菜,其中石莼显著高于裙带菜,IC₅₀值分别为1. 61±0. 17、2. 73±0. 06 mg/mL。相关性分析及冗余分析结果表明,对抗氧化活性影响较为显著的因子为葡萄糖(Glc)、核糖(Rib)、木糖(Xyl)(P <0. 01)。     

羊肚菌多糖提取及其抗氧化活性研究

为了探讨碱法提取羊肚菌多糖的工艺条件并测定其抗氧化活性,该研究以四川北川羊肚菌为原料,采用碱法提取羊肚菌多糖,利用苯酚-硫酸法对羊肚菌多糖得率进行测定,并通过单因素探讨提取温度(70、80、90、100℃)、提取时间(2、4、6、8 h)、碱液浓度(0.4、0.6、0.8、1.0 mol·L~(-1))、料液比(1∶15、1∶20、1∶25、1∶30 g·mL~(-1))对羊肚菌多糖得率的影响,同时采用正交试验优化提取工艺,对其抗氧化活性进行测定。结果表明:在提取温度90℃、提取时间5 h、碱液浓度0.7 mol·L~(-1)、料液比1∶20(g·mL~(-1))条件下得到的羊肚菌多糖得率为5.39%。羊肚菌多糖具有较强的清除DPPH自由基、羟自由基、超氧阴离子的能力和较好的还原能力,其IC50分别为0.468、0.208、0.022、0.014 mg·mL~(-1),抗氧化能力依次为还原能力超氧阴离子清除能力羟自由基清除能力DPPH自由基清除能力。优化后的羊肚菌多糖提取工艺合理、可行,且羊肚菌多糖具有较强的抗氧化活性。     

毛尖茶叶多糖及其结合物的抗氧化活性研究

本研究对毛尖茶叶多糖及其结合物的抗氧化和清除自由基活性开展了研究。采用水提醇沉法提取毛尖茶叶多糖,经除蛋白和纯化后得到精制多糖(MP),将MP在三氟乙酸条件下水解完全,经C18柱层析分离后得到水洗脱部分(MP-HCW)和甲醇洗脱部分(MP-HCM),利用DPPH法和普鲁士蓝法测定MP、MP-HCM和MPHCW的清除自由基和抗氧化能力。结果显示MP、MP-HCM和MP-HCW的DPPH自由基清除率分别为28.99%、13.1%、23.2%;还原力指数分别为0.044、0.015、0.029。实验证明毛尖茶叶多糖及其结合物均有较强药理作用,具有清除自由基和抗氧化活性。     

毛头鬼伞的生物活性作用

毛头鬼伞具有高蛋白、低脂肪等优良特性。毛头鬼伞中含有20种氨基酸,其中人体必需的8种氨基酸全部具备;毛头鬼伞还含有钾、钠、钙、镁、磷等元素和铁、铜、锰、锌、钼、钴等微量元素。目前,毛头鬼伞已被定为符合联合国粮农组织(FAO)和世界卫生组织(WHO)要求的,集天然、营养、保健三种功能为一体的16种珍稀食用菌之一。迄今为止,有关毛头鬼伞生物活性作用的研究还开展得很不充分,国内有少量相关报道,国外对此研究甚少。本文对毛头鬼伞的生物学作用研究现状进行综述,为临床治疗肿瘤、糖尿病、感染性疾病等提供参考。     

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.