模糊C－均值聚类和TWINSPAN分类的比较研究

以英国威尔士北部Ｓｎｏｗｄｏｎｉａ山地Ａｂｅｒ山谷植被为例,对模糊ｃ－均值聚类和ＴＷＩＮＳＰＡＮ分类进行了应用和比较研究。两种方法的结果一致。模糊ｃ－均值聚类结果给出样地和植被类型间的隶属程度,在一定程度上优于ＴＷＩＮＳＰＡＮ。     

三峡大老岭地区森林群落的数量分类研究

在大量的嫩落样方调查基础上,利用二元批示种分类法（ＴＷＩＮＳＰＡＮ）对三峡大老岭地区的森林群落进行数量分类,并据此划人会区山地植被垂直带的高度范围,讨论了ＴＷＩＮＳＰＡＮ方法的特点及其应用于结构复杂的亚热带木时应依据的原则。最后,文章总结了大老岭地区的森林群落类型。     

试用多元分析方法研究植物形态结构与生态环境的关系

应用多元分析方法对栎属高山栎组不同环境条件下的３３个植物样品的形态解剖性状的１７个指标进行了综合分析．结果表明,二元指示种分析（ＴＷＩＮＳＰＡＮ）聚类的结果能很好地把相似生态环境条件下的样品聚在一起,对样品进行无趋势对应分析（ＤＣＡ）和主成分分析（ＰＣＡ）都得到了满意结果．植物形态解剖性状的聚类、排序分析也可用来研究个体性状之间变异的连续性和间断性,进而有助于分类学的研究．     

有序样方聚类在植被垂直带划分中的应用

本文介绍一种非等级分类方法——有序样方聚类法,并将其应用于山西绵山植被垂直带的划分,结果为：１．落叶阔叶林带（包含３个亚带：Ⅰ．落叶阔叶灌丛亚带,Ⅱ．松栎林亚带,Ⅲ．落叶阔叶林亚带）,２．寒温性针叶林带和３．亚高山草甸带。基于黄金分割法（或Ｆｉｓｈｅｒ＇ｓ法）的有序样方聚类法,是按照样方在空间（或时间）先后出现的序号和组内相似性最大,组间相似性最小的标准,对样方进行分类,因此,所得结果是最优的。与ＴＷＩＮＳＰＡＮ的结果比较,在绵山植被遭到严重扰动的情况下,有序样方聚类要优于ＴＷＩＮＳＰＡＮ。     

吕梁山严村低中山区植物群落演替分析

采用一次性同时调查的方法获得数据,用数量分类（ＴＷＩＮＳＰＡＮ）和排序（ＤＣＡ）研究严村低中山植物群落演替。在黄土弃耕地上群落的演替顺序为：苦苣＋狗尾草群落（Ｃｏｍｍ．Ｉｘｅｒｉｓ ｃｈｉｎｅｎｓｉｓ ｓｓｐ．ｖｅｒｓｉｃｏｌｏｒ＋Ｓｅｔａｒｉａ ｖｉｒｉｄｉｓ）→蒿类群落（Ｃｏｍｍ．Ａｒｔｅｍｉｓｉａ ｓｐｐ．）→野艾蒿＋披碱草群落（Ｃｏｍｍ．Ａｒｔｅｍｉｓｉａ ｌａｖａｎｄｕｌａｅｆｏｌｉａ＋     

中国东北西部地区沙质荒漠化过程与植被动态关系的生态学研究：植被的分类

根据东北沙质荒漠化地区呼化贝尔沙地、科尔沁沙地的７２个沙地植物群落样地、２７６种植物的调查数据,进行双向指标种分析（ＴＷＩＮＳＰＡＮ）,结合ＤＣＡ排序得到符合客观实际的分类结果,初步建立了中国东北沙质荒漠化地区植被分类系统,６个植被型,１１个植被亚型,４０个群系,５５个群丛。     

抗真菌蛋白Rs—AFPs基因在大肠杆菌中的表达

将抗真菌蛋白Ｒｓ－ＡＦＰ１和Ｒｓ－ＡＦＰ２全长ｃＤＮＡ插入表达质粒ｐＥＴ－２２ｂ／ＮｃｏＩ＋ＳａｃＩ位点,构建成融合蛋白表达载体ｐＲＡＦ１和ｐＲＡＦ２．将不含信号肽编码序列的Ｒｓ－ＡＦＰ１和Ｒｓ－ＡＦＰ２ｃＤＮＡ分别插入ｐＥＴ－２２ｂ／Ｎｃｏｌ＋Ｓａｃｌ和ｐＥＴ－２２ｂ／Ｎｄｅｌ＋ＳａｃＩ位点,构建成不含信号肽序列的融合蛋白表达载体ｐＲＡＦ３、ｐＲＡＦ４和非融合蛋白表达载体ｐＲＡＦ５和ｐＲＡＦ６．将构建的上述各种表达载体转化Ｅ．ｃｏｌｉＢＬ２１,挑菌落培养,ＩＰＴＧ诱导,使Ｒｓ－ＡＦＰｓ基因得到表达,并用体外抑菌试验检测表达产物的活性,结果表明,各种表达载体的表达产物均具有不同程度的抑菌活性,其中,ｐＲＡＦ３和ｐＲＡＦ４表达产物的抑菌活性较明显．     

PARP酶抑制剂未引起整合的外源LacZ基因的丢失

使用聚ＡＤＰ核糖聚合酶（ＰＡＲＰ）ＮＡＤ位点抑制剂苯甲酰胺（ＢＡ）研究了降低ＰＡＲＰ酶活性对外源ＬａｃＺ基因整合稳定性的影响,利用ＤＮＡ体外重组技术将ＬａｃＺ基因全序列插入到真核表达载体载体ＰＳＶ２ｎｅｏ的ＨｉｎｄⅢ位点,构建了一个具有真核细胞ｎｅｏ基因筛选标记和ＬａｃＺ基因的真核表达重组体ＰＳＶ２ｎｅｏ－ｂｅｔａ－ｇａｌ将该重组体导入ＨｅＬａ细胞,经Ｇ４１８筛选获得了能稳定表达β－半乳糖苷酶的Ｈ     

吉林梅花鹿体尺,体重聚类与主成分分析

吉林梅花鹿体尺、体重聚类与主成分分析ＤＬＵＳＴＥＲＡＮＤＰＲＩＮＣＩＰＡＬＣＯＭＰＯＮＥＮＴＡＮＡＬＹＳＩＳＯＦＴＨＥＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＡＮＤＷＥＩＧＨＴＯＦＪＩＬＩＮＳＩＫＡＤＥＥＲ￥ＬＩＨｅｐｉｐｇ;ＢＩＮＧＧｕｏｌｉａｎｇ;ＰＡＮＧ...     

栝楼种子中一种新型小分子核糖体失活蛋白——S—tric …

通过硫酸铵分级沉淀、ＣＭ－５２阳离子交换层析、Ｓｅｐｈａｃｒｙｌ Ｓ－１００凝胶过滤和ＦＰＬＣ Ｍｏｎｏ－Ｓ离子交换层析等步骤,从栝楼种子中分离到一种核糖体失活蛋白－－Ｓ－ｔｒｉｃｈｏｋｉｒｉｎ,经１５％ＳＤＳ－ＰＡＧＥ测定分子量为８ｋＤ左右,１３．５％聚丙烯酰胺凝胶酸性电泳结果显示其等电点在ｐＨ９．５左右。通过对大鼠肝核糖体作用的研究,表明Ｓ－ｔｒｉ－ｃｈｏｋｉｒｉｎ属于ＲＮＡ Ｎ－糖苷酶催化型     

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.