微波消解-石墨炉原子吸收光谱法测定大鼠组织中的微量硒

目的:建立微波消解石墨炉原子吸收光谱法(GFAAS)测定大鼠组织中的微量硒的检测方法.方法:采用微波消解法处理样品,用硝酸作为消解剂进行微波消解;采用氯化钯则作为基体改进剂来测定样品中的微量硒.结果:最佳灰化温度为900℃,原子化温度为2500℃;脑组织和肺组织的相对标准偏差(RSD)分别为2.83％和3.05％,样品加标回收率为97％～105％.结论:该方法用于检测大鼠组织中的硒含量,操作简便、快速、准确度好、结果满意,能够适用于生物体内多种组织器官中硒含量的测定与分析.     

柱前衍生反相高效液相色谱法测定绞股蓝茶叶中17种游离氨基酸含量

建立2,4-二硝基氟苯柱前衍生化-反相高效液相色谱法测定绞股蓝茶叶中17种游离氨基酸的含量。以Phenomenex Gemini NX C18(4.6mm×250mm,5μm)为分析柱,采用梯度洗脱,流动相A为0.05mol·L-1乙酸钠(pH=6.4,含0.1%N,N-二甲基甲酰胺),流动相B为乙腈-水(1∶1,v/v),检测波长为360nm,柱温35℃;经方法学考察,该方法具有良好的稳定性和重现性。测定结果表明,绞股蓝茶叶中17种游离氨基酸总量为39.79mg·g-1,其中人体必需氨基酸占游离氨基酸总量的36.57%。从氨基酸含量考虑,绞股蓝茶叶具备一定的开发利用价值。     

绞股蓝皂苷-硒配合物对酪氨酸酶的活性影响及动力学分析

为考察绞股蓝皂苷及其硒配合物对酪氨酸酶的动力学参数和作用机理。本研究采用体外酶促反应,以L-酪氨酸和L-DOPA为底物,模拟了酪氨酸酶单酚和二酚酶的体外催化氧化过程。绞股蓝总皂苷在50%、70%乙醇洗脱段和50%、70%乙醇洗脱绞股蓝皂苷-硒配合物在酪氨酸酶上的Ki值分别为1. 533、1. 767、1. 312和1. 210 mmol/L。Ki值越低,对酪氨酸酶的抑制作用越强,单酚酶的氧化阶段越快,表明硒元素显著提高了绞股蓝皂苷对酪氨酸酶的抑制作用。酶反应动力学分析表明,四种绞股蓝皂苷及其硒配合物对酪氨酸的抑制作用均为混合竞争抑制。其独特的药理化学特性为绞股蓝及硒系美白化妆品的进一步研究开发提供了理论依据和参考。     

茶叶中总硒含量及其影响因素的研究

茶叶中硒素总量测定结果表明：土壤含硒量的高低是直接影响茶叶中硒的总量。茶树根、茎、叶、果中均有硒元素,叶片是茶硒积累的主要器官,尤其是老叶,其含量是嫩叶的几倍．茶树品种间含量的差异显著,最大差异达10倍以上．毛茶加工的成品茶含硒量受加工技术措施影响较大,其不同等级的含硒量与级别没有线性关系．     

绞股蓝总皂甙提取方法的比较研究

目的：探讨绞股蓝总皂甙最佳的提取方法。方法：首先选用水、80％甲醇、75％乙醇和氯仿等作为溶剂提取绞股蓝总皂甙,从中选择出2种较优试剂,再以回流提取法、索氏提取法、超声波法等提取方法对绞股蓝的总皂甙进行提取,从而选出一种优良的提取方法。并且采用分光光度法测定了绞股蓝总皂甙的含量。结果：研究表明,75％乙醇为绞股蓝总皂甙提取的最佳溶剂,乙醇回流提取法为最优方法。结论：以75％乙醇为提取溶剂的回流提取法是一种高效、简便、节能的绞股蓝总皂甙的提取方法。     

海南岛绞股蓝属植物中总氨基酸分析

应用日立８３５５０型氨基酸自动分析仪对海南岛不同生境绞股蓝属５种植物中的总氨基酸组分进行了含量测定与比值分析。结果表明：绞股蓝（５４．１１％）＞单叶绞股蓝（５３．８０％）＞光叶绞股蓝（４４．９８％）＞喙果绞股蓝（３５．５８％）＞毛果绞股蓝（１７．５０％）。各种样品均含有１７种氨基酸,Ｇｌｕ、Ｓｅｒ、Ｇｌｙ和Ａｓｐ含量最高,Ｍｅｔ、Ｃｙｓ、Ｈｉｓ偏低;栽培的高于野生的,量值相比变化范围达０．７％～２．７０９％;５种绞股蓝游离氨基酸定量分析结果,以单叶绞股蓝和绞股蓝含量最高（１３．４０５％、１２．９０４％）、喙果绞股蓝与光叶绞股蓝居中（１１．４８％、１１．１６３％）、毛果绞股蓝稍为偏低（７．６８０％）。     

张家界市部分农作物可食部位硒含量研究

采用国家标准( GB/T5009.93-2003),用荧光分光光度计对张家界市22种农作物40个样本可食部位中的硒含量进行了分析.结果表明,测定的22个种类40个样本均属于富硒及高硒作物,以茶叶的硒平均含量最高为2.0102 mg/kg,其次是豆类平均含量为1.8518 mg/kg,薯类含量最低为1.0240 mg/kg.所测定的各种作物可食部位富硒能力依次为:茶叶2.0102 mg/kg＞豆类(干)1.8518 mg/kg＞水稻、玉米1.5326 mg/kg＞蔬菜类1.3438 mg/kg＞水果类1.0783 mg/kg＞薯类1.0240 mg/kg.该研究确定了部分农作物硒含量的水平及富硒作物品种.     

海南岛绞股蓝植物中总氨基酸分析

应用日立８３－５０型氨基酸自动分析仪对海南岛不同生境绞股蓝属５种植物中的总氨基酸组分进行了含量测定比值分析。结果表明：绞股蓝（５４．１１％）〉单叶绞股蓝（５３．８０％）〉光叶绞股蓝（４４．９８％）〉果绞股蓝（３５．５８％）〉毛果绞股蓝（１７．５０％）。各种样品均含有１７种氨基酸,Ｇｌｕ、Ｓｅｒ、Ｇｌｙ和Ａｓｐ含量最高,Ｍｅｔ、Ｃｙｓ、Ｈｉｓ偏低;栽培的高于野生的。量值相比变化范围达０．７－２．７０     

五指山不同级别新鲜苦丁茶微量元素含量测定

采用火焰原子吸收光谱法对海南五指山苦丁茶不同级别新鲜茶叶中的锌、铁、钙、钾、镁五种元素进行了含量测定,详细地研究了消解酸的种类、HNO3、HCIO4和H2O2的比例、消解酸的体积及消解时间对测定结果的影响。用HNO3-HClO4-H2O2处理样品,测定结果表明不同级别苦丁茶茶叶中均含有丰富的人体必需的微量元素,不同等级的苦丁茶中微量元素含量有差异,但,其含量排序均为KCaMgZnFe,一级苦丁茶中Zn、K、Mg这3种微量元素的含量高于其他等级,而三级苦丁茶中Ca、Fe这2种微量元素含量要高于一、二级的苦丁茶,但总体差别不大。采用此方法回收率为101.38%～103.10%,相对标准偏差小于10%。其方法简便、精密度和灵敏度高,结果令人满意。     

绞股蓝对人体血小板聚集功能及微循环的影响

绞股蓝[Gynostemma Pentaphyl lum(Thunb)Makino]为葫芦科绞股蓝属多年生草质藤本植物湖北郧阳地区有广泛分布,质量较上乘,含有人体必需的微量元素如锌、硒、钙、铁等.1983年日木常松等先后对绞股蓝进行了一系列化学研究,从中分离得出许多种皂甙及多糖,可视为原人参醇或     

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.