山楂原花色素的抗氧化作用研究

本文用比色法测定山楂原色素（Proanthocyanidins from the fruits of hawthorn,HPA)的抗氧化作用,即对羟自由基、超氧负离子的清除作用以及抗脂质过氧化的作用,并且通过细胞学实验验证其对上皮细胞的抗氧化损伤的保护作用。试验表明：山楂原色素有很强的抗氧化作用,其作用在浓度为0．1mg/ml-1.0mg/ml之间随着浓度的增大而增强,对超氧负离子的清除和抗脂质过氧化作用尤为明显。在浓度为1mg/ml时,对羟自由基和超氧负离子的清除率分别为59．8％和90．0％,对细胞氧化损伤的保护率为41．96％;浓度为0．5mg/ml时对脂质过氧化的抑制率达91．9％。试验同时还比较了葡萄籽原花色素（Proanthocyanidins from the fruts of grape,GPA)和Vc的抗氧化作用,结果表明：山楂原花色素与葡萄素（Proanthocyanidins from the fruits of grape,GPA)和Vc的抗氧化作用,结果表明：山楂原色素与葡萄籽原花色素效应相当,并远远高于Vc的效应。     

金银花尺蠖幼虫粪便乙醇提取物体外抗氧化活性

自由基过量累积会影响生物体正常机能,筛选具有自由基清除功能的昆虫代谢产物对于开发虫茶至关重要。为了解金银花尺蠖幼虫粪便提取物的抗氧化活性,在室内测定了金银花尺蠖幼虫粪便乙醇提取物的体外抗氧化活性。结果表明,金银花尺蠖幼虫粪便乙醇提取物具有一定的体外抗氧化活性:对二苯代苦味酰自由基(DPPH)、羟基自由基(·OH)、超氧阴离子自由基(O-·2)、ABTS+·自由基均具有一定的清除能力,在0.05mg/m L时的清除率分别为37.78%、25.31%、21.41%和35.82%;随着提取物浓度的增大,对自由基的清除率逐渐增加,当浓度上升到0.65 mg/m L时的清除率分别为95.52%、69.07%、63.27%和72.46%,分别增加了57.74%、43.76%、41.86%和36.64%,差异达显著水平;对卵黄脂蛋白脂质过氧化也具有一定的抑制作用,在0.05 mg/m L时的抑制率为26.78%,随着提取物浓度的增大,对脂质过氧化的抑制率也逐渐增加,当浓度上升到0.65 mg/m L时的抑制率为50.63%,增加了23.85%,差异达显著水平。在0.05~0.65 mg/m L的浓度范围内,对自由基的清除率、对脂质过氧化的抑制率与浓度之间呈显著的线性关系。综上,金银花尺蠖幼虫粪便提取物具有开发为虫茶的潜力。     

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。     

炭团菌提取物对樟子松枯梢病菌的抑菌活性及稳定性研究

采用水提和酯提2种方式提取炭团菌液体培养菌液中高效抑制樟子松枯梢病菌活性物质。采用生长速率法测定提取物对病原菌菌丝生长的抑制率,采用悬滴法测定其对病原菌孢子萌发的抑制率。炭团菌液体培养菌液乙酸乙酯提取物稳定性试验选用紫外线、温度、pH、氧化剂与还原剂以及贮存时间5个因子。结果表明:炭团菌液体培养菌液的5种提取物对樟子松枯梢病菌均有一定的抑菌活性,乙酸乙酯提取物对病原菌菌丝生长的抑制率最高,达到73.20%;乙酸乙酯提取物、超声波提取物、正丁醇提取物对病原菌孢子萌发抑制率均超过90%。乙酸乙酯提取物对自然环境下的紫外线、温度具有很高的稳定性,并且有一定的抗氧化还原能力和良好的耐热性,长期贮存不影响其抑菌活性,具有很高的开发价值和很好的应用前景。     

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。     

显齿蛇葡萄提取物抗油脂氧化作用研究

用显齿蛇葡萄Ampelopsis grossedentata幼嫩茎叶提取物进行抗氧化试验,结果表明:显齿蛇葡萄幼嫩茎叶提取物有很强的抗氧化作用.0.2%的显齿蛇葡萄提取物对油脂的抗氧化效果超过同浓度的BHA及生姜提取物,0.7%的显齿蛇葡萄提取物对菜油、猪油的氧化抑制率比0.2%的BHA分别高出49.8%、9.4%,比0.2%生姜提取物分别高出46.5%、62.2%.     

三种中药提取物对黄嘌呤氧化酶的抑制作用

分别用水、60%乙醇和95%乙醇为提取溶剂,对泽泻、青风藤和白芷进行提取,通过测定黄嘌呤氧化酶(XOD)-黄嘌呤反应体系终产物尿酸的吸光度,得出各提取物对XOD的抑制率,并判断其抑制机制。实验结果显示,在一定浓度范围内,泽泻和青风藤两种醇提物对XOD的抑制率较高,泽泻60%乙醇提取物抑制率最高达86%,青风藤95%乙醇提取物抑制率最高为71.2%,白芷水提取物对XOD抑制率较高,最高为72.7%。结果表明,三种中药的提取物均具有较强的体外抑制XOD活性的作用。     

不同生长期香椿叶片的抗氧化活性及其抗氧化作用分析

采用分光光度法,研究了不同生长期香椿叶片的抗氧化活性,并对其抗氧化作用进行了分析。结果表明,阴干处理对香椿总抗氧化力无显著影响,不同生长期的香椿总抗氧化力无显著差异;香椿嫩芽、嫩叶和老叶提取物均有清除.OH的作用,老叶、嫩叶对.OH的清除率均显著大于嫩芽,且阴干香椿对.OH的清除率均显著高于同一生长期的新鲜香椿,尤以阴干老叶的清除率最高;不同生长期的香椿提取物均有抑制亚油酸过氧化的作用,在低浓度时,嫩芽提取物对亚油酸过氧化的抑制率显著高于嫩叶或老叶,而在高浓度时,不同生长期香椿叶提取物对亚油酸过氧化的抑制率无显著差异。     

苦荞多肽的纯化、结构与体外抗氧化活性研究CSCD

为了探究苦荞多肽粗提液抗氧化活性的主要来源,需要进一步对苦荞多肽进行分离纯化,通过结构鉴定来分析抗氧化活性与多肽结构之间的关系。该研究以苦荞功能提取物废渣为原料提取苦荞粗蛋白辅以植物乳杆菌发酵法制备苦荞多肽,采用大孔吸附树脂、葡聚糖凝胶、液相色谱对苦荞多肽粗提液进行分离纯化,并以抗氧化活性为指标,筛选抗氧化活性较强的组分,利用液相色谱-质谱联用技术鉴定抗氧化多肽结构。结果表明,纯度不同的苦荞多肽抗氧化能力也不同,经过Sephadex G-15葡聚糖凝胶分离纯化得到的T-3组分ABTS和DPPH自由基清除能力最优,清除率分别为96%、94%。纯化后苦荞多肽的抗氧化活性显著高于粗提液(P<0.05),但是抗氧化活性并没有完全与苦荞多肽纯度呈正相关,通过液相色谱进一步分离纯化T-3组分后得到的组分T-3-1,苦荞多肽纯度虽然达到了98%,但是对DPPH和ABTS抑制率不再增强,反而稍有下降,抑制率分别为89%和90%。由质谱鉴定结果得到,主要抗氧化肽的氨基酸序列为苯丙氨酸-脯氨酸-酪氨酸Phe-Pro-Tyr(FPY)和酪氨酸-亮氨酸-脯氨酸-苯丙氨酸Tyr-Leu-Pro-Phe(YLPF)。研究结果以期为苦荞多肽的进一步开发利用提供一定的理论基础。     

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。     

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.