钮子七提取物的抗氧化作用及对胃癌细胞的抑制作用

以钮子七提取物为材料,通过邻苯三酚自氧化法测定钮子七提取物对超氧阴离子生成的影响,通过邻二氮菲溶液测定钮子七提取物对羟自由基的清除作用;采用噻唑蓝(MTT)法测定钮子七提取物对胃癌细胞生长的影响。结果显示,钮子七水提取物和70%乙醇提取物对超氧阴离子的产生有较强的抑制作用,在浓度大于5.0 mg/m L时,抑制作用显著增强。钮子七70%乙醇提取物和水提取物均有清除羟自由基的作用,在浓度大于2.5 mg/m L时清除作用显著增强。钮子七水提物和乙酸乙酯提取物在24 h、48 h及72 h后对胃癌细胞均有抑制作用,且都以作用72 h后抑制作用最强。结果表明,钮子七提取物具有较强的抗氧化作用以及较强的抑制胃癌细胞的作用。     

黄芩提取物抗氧化性及其对肝癌HepG-2细胞的抑制作用

本研究探讨黄芩提取物的抗氧化能力以及对肝癌细胞HepG-2生长的影响。通过分光光度法、邻苯三酚自氧化法测定不同黄芩提取物对DPPH自由基、超氧阴离子的清除效果,以此考察其抗氧化性能;同时采用MTT法测定不同黄芩提取物对HepG-2细胞的生长影响来研究其抗肿瘤作用。结果显示,3种不同的黄芩提取物均具有较好的抗氧化性能,并对肝癌细胞的生长具有明显的抑制作用,黄芩正丁醇部分、黄芩乙酸乙酯部分及黄芩石油醚部分对肝癌细胞作用72h后,对HepG-2细胞的最大抑制率分别达到57.2%、51.8%和35.2%。3种黄芩提取物具有较强的抗氧化活性,且对肝癌细胞的生长有一定的抑制作用。     

红果参提取物的抗氧化活性研究

超声辅助提取红果参中的抗氧化活性物质并用D-101大孔树脂纯化,以原花青素为指标测定抗氧化活性物质含量,研究了提取物对羟基自由基、超氧阴离子自由基和亚硝酸盐体系的清除作用以及对油脂氧化体系的抑制作用。结果表明:红果参果实提取物表现出了对羟自由基、超氧阴离子自由基及亚硝酸盐的优异的清除能力,对油脂氧化有极好的抑制作用,对自由基的清除率及抗油脂氧化能力与提取物中原花青素质量浓度均呈剂量正相关效应。     

索骨丹提取物对人胃癌细胞MGC80-3的抑制作用

用不同浓度的索骨丹乙酸乙酯提取物和乙醇提取物干预培养的人胃癌细胞,采用MTT法观察各浓度提取物对胃癌细胞活性的影响,免疫细胞化学方法检测胃癌细Bcl-2和Bax的表达,运用ELISA方法检测PGE2生成量,以探讨索骨丹提取物抑制胃癌细胞生长的作用机制。结果显示不同浓度的两种提取物对胃癌细胞的增殖活性均有抑制作用,以48 h和72 h作用显著(P0.05)。40 mg/m L和10 mg/m L提取物均可明显减少Bcl-2的表达而增强Bax的表达(P0.05)。两种提取物均可降低胃癌细胞PGE2的生成量,以浓度40 mg/m L和10mg/m L作用显著(P0.05)。推断索骨丹提取物可能通过调整Bcl-2和Bax的表达而促使细胞凋亡,并通过降低PGE2的生成而抑制胃癌细胞的增殖。     

家蝇幼虫提取物清除氧自由基的作用

探讨了家蝇Musca domesticaL.幼虫提取物对氧自由基的清除作用。采用脱氧核糖-铁体系和邻苯三酚自氧化体系分别测定了不同浓度的提取物对羟自由基和超氧阴离子自由基的清除率,同时采用H2O2氧化体系测定了提取物的抗氧化值。结果显示家蝇幼虫提取物对羟自由基和超氧阴离子自由基的IC50分别为1.93 mg/mL和3.26 mg/mL;浓度为0.5%的提取物的抗氧化值为9.01 mg/g,为同浓度维生素C抗氧化值的1.29倍。     

皂荚棘刺提取物总黄酮提取测定、除螨活性及抗氧化活性研究

目的：对皂荚棘刺提取物的除螨及抗氧化活性进行探究。方法：检测皂荚棘刺提取物处理前后螨虫的自然死亡率和提取物的灭螨率，同时测定提取物对DPPH自由基、超氧阴离子自由基以及Fe3+的清除能力，判断皂荚棘刺提取物的除螨能力及抗氧化能力。结果：所得皂荚棘刺提取物的黄酮提取率为0.136%，其体外抗氧化实验表明皂荚皂素对DPPH自由基、超氧阴离子自由基均有明显的清除作用，且48 h除螨活性达到91%。结论：皂荚棘刺提取物具有良好的除螨活性及抗氧化活性，具有良好的应用前景。     

青蒿内生真菌Alternaria sp.(PQH12)提取物体外细胞毒活性及抗氧化活性的研究

本文分别采用环己烷、正丁醇、乙酸乙酯、丙酮、甲醇5种极性不同的溶剂分别提取青蒿内生真菌Alternaria sp.(PQH12)的菌丝体。采用MTT法分别测定不同极性溶剂提取物对3种肿瘤细胞株(HL-60、MCF-7和COLO205)的生长抑制率,采用DPPH自由基清除法和超氧阴离子O-·2清除法评价了青蒿内生真菌Alternaria sp.(PQH12)不同极性溶剂提取物的抗氧化活性。结果显示,正丁醇和乙酸乙酯提取物均表现出对肿瘤细胞生长的抑制作用;浓度为20μg/mL时,正丁醇提取物对HL-60细胞的生长抑制率为80.56%,乙酸乙酯提物对MCF-7和COLO205细胞的生长抑制率分别为54.47%和83.09%;在两种抗氧化活性评价体系中,甲醇提取物的抗氧化活性均明显优于其他溶剂的提取物,其IC50值分别为0.20 mg/mL(DPPH)和0.19 mg/mL(O-·2)。该结果表明,青蒿内生真菌Alternaria sp.(PQH12)具有较好的细胞毒和抗氧化潜力,具有一定的开发利用价值,可以作为进一步实验研究的对象。     

沙苑子酚类提取物的抗氧化能力研究

为有效开发利用沙苑子,探究其抗氧化特性为深加工提供理论依据和经验参数,本文主要从沙苑子酚类提取物的总还原能力,对超氧阴离子自由基和羟基自由基的清除能力,及对Fe2+诱导的脂质过氧化的抑制作用等四个方面进行了研究并比较了三种不同沙苑子酚类提取物的抗氧化性能。结果表明沙苑子酚类提取物均具有一定的抗氧化能力,在实验浓度范围内呈现一定的量效关系。     

板蓝根抗氧化成分及抗氧化性能研究

目的:研究板蓝根抗氧化成分及抗氧化性能,为板蓝根提取物抗衰老、抗肿瘤等领域的开发利用提供科学依据。方法:本文采用系统的分离方法,从板蓝根中提取黄酮、多糖、多酚及生物碱四种成分,并采用Schaal烘箱法、邻苯三酚法、水杨酸法测定板蓝根四种提取物的总抗氧化能力、清除超氧阴离子(O_2~-·)及清除羟自由基(·OH)能力。结果:板蓝根提取物对三种食用油脂均有良好的抗氧化效果,且对抗氧化作用具有剂量效应关系;Vc、柠檬酸及酒石酸对板蓝根提取物的抗氧化作用均有协同增效作用;板蓝根提取物对超氧阴离子(O_2~-·)和羟自由基(·OH)有良好的清除作用,且清除作用具有剂量效应关系;其中板蓝根提取物生物碱和黄酮分别对超氧阴离子(O_2~-·)和羟自由基(·OH)清除作用较强。结论:板蓝根取物具有良好的抗氧化作用,可将其作为一种天然的抗氧化剂应用于油脂、食品及日用品中;也可将其应用于抗衰老,抗高血脂药物研究中,进一步开发其药用价值。     

南瓜多糖衍生物的制备及其抗氧化研究

对超声辅助法提取的南瓜粗多糖,进行化学改性得到了硫酸化南瓜多糖和羧甲基南瓜多糖。用邻苯三酚自氧化法检测对超氧阴离子自由基的清除作用,用邻二氮菲-金属铁离子-H2O2体系检测对羟自由基的清除作用。结果表明,南瓜多糖对超氧阴离子自由基无抑制作用,经化学改性后的羧甲基南瓜多糖和硫酸化南瓜多糖对超氧阴离子自由基有明显抑制作用,最大清除率达44％和41．67％。以上3种多糖均能有效清除·OH,随着浓度的增加清除作用加强,最大清除率可达46．49％,22．61％和42．35％0。结果显示,经化学改性后的南瓜多糖有较强的抗氧化作用。     

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.