共查询到20条相似文献,搜索用时 78 毫秒
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傅亚珍 《生物化学与生物物理进展》1986,13(2):23-29
热容是描述宏观系统状态的基本热力学函数——焓对温度的导数,即c_p=dH(T)_p/dT人们之所以要对一个系统进行热容测量,是因为用作为焓的导数的热容去描述系统的状态对温度的依赖关系要比用焓去描述更为严谨。某些热分析技术(如差示扫描量热技术DSC)直接测量的正是热容而不是焓变参数。 相似文献
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几种定向进化技术的比较及文库构建策略 总被引:6,自引:0,他引:6
蛋白质定向进化在蛋白质工程中取得了令人瞩目的成就,其核心技术---随机突变库构建技术已成为近年来体外定向进化研究的热点。在概述定向进化基本原理基础上,对几种随机突变技术进行了介绍、分类和比较,并对突变库的特征及构建策略予以分析和描述 。 相似文献
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实时荧光定量PCR及其在微生物生态学中的应用 总被引:15,自引:0,他引:15
定量描述微生物群落的组成,在微生物生态学的许多研究领域都是非常重要的。然而由于可培养技术的局限性,定量描述微生物群落成为比较困难的事情。最近包括PCR技术在内的分子生物学技术为人们提供了有力的工具,使对微生物群落的分布、丰度等有了进一步的了解。实时荧光定量PCR技术作为核酸定量检测技术,自从发明以来在微生物生态学研究中逐渐得到了广泛的应用。从微生物生态学角度,综述了实时荧光定量PCR技术的原理、发展、优缺点及其在微生物生态学研究中的应用与研究进展,并探讨了实时荧光定量PCR技术的发展和应用前景。 相似文献
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原位PCR技术及其应用前景 总被引:4,自引:0,他引:4
原位PCR是分子生物学领域中一种崭新的技术,它结合了PCR技术和原位杂交技术的优点.该文介绍了原位PCR技术的起源、发展及方法学,并简要描述了该技术的应用现状及前景. 相似文献
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中国蔷薇科一新属--多蕊石灰树属 总被引:2,自引:0,他引:2
技术了中国蔷薇科一新属,多蕊石灰树属和属下的唯一分类单位多蕊石灰树。在新分类群描述了基础上,据形态学资料对其进行了初步的系统学讨论。 相似文献
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弹性是一种描述物质物理意义的重要参数,在描述物质在热力学和动力学的变化过程中有着重要的意义。在医学上,弹性的变化往往和病变联系在一起。然而,绝大多数生物组织在他们的力学特性上所表现出的复杂性并不是弹性模量一项参数就可以完全表述的,在对于他们的粘弹性表征和流变学行为的描述中,粘滞性往往和弹性一样的重要。现在被广泛用来对生物组织机械特性表征的成像技术是弹性成像,其基本原理是给组织施加一个激励,组织会产生一个响应,而该响应的分布结合技术的处理方法,可以反映出其弹性模量等力学属性的差异。本文介绍了生物组织常见的弹性成像方法:超声弹性成像,磁共振弹性成像以及光学相干弹性成像;详细阐述了新发展起来的技术-光声弹性成像和光声粘弹成像,并讨论分析其应用前景。 相似文献
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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. 相似文献
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RICHARD E. NORRIS 《Botanical journal of the Linnean Society. Linnean Society of London》1991,106(1):1-40
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. 相似文献
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JOAN VALUÈS MONTSERRAT TORRELL NÚRIA GARCIA JACAS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):399-407
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. 相似文献
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肝癌中HBV和HCV基因和抗原的分布及意义 总被引:1,自引:0,他引:1
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 相似文献
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H.-R. GREGORIUS 《Biological journal of the Linnean Society. Linnean Society of London》1984,23(2-3):157-165
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. 相似文献
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. 相似文献