复合四倍体异育银鲫个体间遗传异质性的研究

用聚丙烯酰胺梯度凝胶电泳,分析比较了４个不同的银鲫雌核发育系,红鲤和复合四倍体异育银鲫鳍的５种不同的同工酶及蛋白表型的差异,表明复合四倍体异育银鲫表型上的差异主要是来自银鲫种内的遗传差异（不同的雌核发育系）。来源于同一个银鲫雌核发育系的复合四倍体异育银鲫,个体间的ＥＳＴ同工酶出现差异,并与父体红鲤的ＥＳＴ同工酶的多态性相关,因此,复合四倍体异育银鲫个体间的异质性也包含了来自父本的遗传影响。在所检测     

异源精子在银鲫雌核发育子代中的生物学效应

黑龙江省方正县双凤水库的两性型银鲫群体是三倍体雌核发育种群。异源精子不仅能刺激银鲫卵雌核发育,而且还能影响雌核发育子代的某些性状,如对于子代的生长、性比、体色和肝脏LDH同工酶等都产生了影响。为区别于原有术语“雌核发育gynogenesis”,我们把这种表现了异源精子生物学效应的雌核发育称之为“异精雌核发育allogynogenesis”,发育的子代称之为“异育银鲫”。异育银鲫已以其明显的生长优势在生产上显示了优良的经济性状。       

复合四倍体异育银鲫的血红蛋白和红细胞的同工酶分析

用聚丙烯酰胺梯度凝胶电泳,分析了银鲫、复合四倍体异育银鲫和红鲁的血红蛋白及红细胞中的４种不同的同工酶。结果表明复合四倍体异育银鲫的一些座位,除了银鲫的基因表达外还观察到红鲤基因的表达,出现了银鲫原来所没有的区带或原有的区带受到抑制等现象,显示出复合四倍体异育银鲫具有类似于杂种的遗传性状,另一方面从４种不同的 同工酶表型分析,表明复合四倍体异育银鲫的同工酶基因表达较接近银鲫。     

雌核发育银鲫的受精生物学研究——天然雌核发育银鲫繁殖方式的讨论

本文研究了同源雌核发育银鲫精子在4种类型的雌核发育银鲫卵中的发育特征。初步揭示了天然雌核发育银鲫根据精子的来源不同而分别具有二种不同的繁殖方式,对其在维持雌核发育银鲫种群生存,促使克隆分化等方面的独特的生物学意义进行了讨论。     

银鲫不同雌核发育系的生物学特性比较研究

银鲫不同雌核发育系间,以D系银鲫体型最高,其相对体高平均为47％,A系为44.4％,C系为43.7％,B系为41.7％。在生长速度方面以D系生长最快,其次为A系,这两个系的银鲫在含肉量与肌肉蛋白质含量上均无明显差异,但D系银鲫对饵料的利用效率明显高于A系,因此生产上养殖以D系银鲫为母本,红鲤为父本人工繁殖而成的高体型异育银鲫,可提高经济效益10—20％。银鲫4个雌核发育系的卵巢发育进程不同,D系卵母细胞在2月份有个迅速发育期,因而最早进入成熟产卵期。A系成熟产卵期略晚,C系成熟产卵期较迟。银鲫染色体数目存在系间差异,D系染色体数目为162,A系和C系为156。     

雌核发育进行银鲫遗传育种新进展

近年来,人工诱导雌核发育作为一种崭新的技术在鱼类遗传育种研究中正日益引起人们的普遍关注。银鲫作为天然雌核发育的代表,以其独特的生殖方式和重要的经济价值,在理论研究和生产实践中均具有重要意义,本文概要介绍了银鲫的生殖方式,天然群体中优良品系的选育、异源精子对银鲫子代的生物学效应及其在生产实践中的应用－异育银鲫的选育,以及结合染色体倍性操作技术培育四倍体复合鲫的研究近况及发展前景。     

Cytological Mechanism on the Integration of Heterologous Genome or Chromosomes in the Unique Gynogenetic Carassius auratus gibelio

银鲫（ＣａｒａｓｉｕｓａｕｒａｔｕｓｇｉｂｅｌｉｏＢｌｏｃｈ）是行天然雌核发育生殖的两性型三倍体鱼类,与普通两性融合生殖鱼类相比,具有独特的育种优势。八十年代以来,异育银鲫、复合四倍体异育银鲫的发现表明,雌核发育卵子不但具有保持自身全部染色体的能力,还能整合异源精子的部分遗传物质或整个基因组,影响雌核发育后代的性状。因此,搞清楚异源基因组的整合机制对于进一步弄清其发育模式以及诱导复合多倍体银鲫均具有十分重要的作用。两性融合发育鱼类的精子入卵后,精核在促精核活化因子的诱导下,可以逐渐解凝并形成雄性原核;而在天然雌核发育银鲫受精卵中,精核的解凝和原核化却被抑制。去掉卵壳的控制作用后,精核虽能在卵质中解凝却仍不能形成雄性原核（Ｆｉｇ．１）。可见,雌核发育银鲫与两性融合发育鱼类的卵质间必定存在某些差异。对哺乳类和两栖类卵质诱导精核原核化作用的研究表明,ＤＴＴ和蛋白水解酶能够分别还原精核组蛋白中ＳＳ和水解精核组蛋白,从而诱导精核在卵质中形成雄性原核。本文通过显微注射以及冷休克处理等诱导方法,探讨了人工诱导外源精核在银鲫卵中解凝和原核化,培育银鲫复合种的细胞学机制。实验结果显示,向银鲫卵质中注入胰蛋白酶、ＤＴＴ和     

人工转性异育银鲫精子在两性融合型和雌核发育型卵质中的发育特征及其应用意义

通过甲基睾丸素诱导产生的雄性雌核发育银鲫产生的精子,能与两性融合生殖的鲤鱼卵受精结合,并能正常地转化为雄性原核。但在卵裂开始后,可观察到诸如核物质丢失、多极分裂等异常现象。从而进一步证实了作者过去提出的染色体不相容假设。转性异育银鲫精核在雌核发育银鲫卵中能初步地转化为雄性原核,但其发育程度低于雌核。根据双重控制假设,作者初步认为,转性异育银鲫精子在进入雌核发育型卵的过程中没有受到初级控制的作用。这或许是因为转性雄鱼的雌性遗传基础导致精子的某种特异性因子缺失的缘故。由于雌核发育银鲫卵质中次级控制的存在,使得解凝的精核不能完全转化为雄性原核。     

滇池高背鲫和方正银鲫酯酶和乳酸脱氢酶的比较研究

本研究以方正银鲫酯酶(Carassius auratus gibelio Bloch)普通鲫(Carassius auratus)和滇池高背鲫(Carassius sp.)的各种组织器官为材料, 进行酯酶(Esterase)和乳酸脱氢酶(LDH)同工酶电泳图谱的分析比较.结果表明:9种不同组织中酯酶同工酶谱带各不相同,有明显的组织特异性.滇池高背鲫的酯酶谱图有3种表型.正方银鲫和滇池高悲鲫同一组织的LDH同工酶谱也有明显差异. 等电聚焦凝胶电泳(T=7.5%,C=5%)的结果又表明这二种鱼的肝脏, 脑, 卵的酯酶同工酶谱及电泳扫描图有差异. 这些结果揭示滇池高背鲫与方正银鲫至少在生化水平上已有明显的分化, 很可能起源于不同的地区,由不同的祖先,独立演化而形成. 滇池高背鲫与云南普通鲫的LDH酶谱较为接近,这说明滇池高背鲫最可能起源于云南本地的普通鲫.     

异育淇鲫及其双亲同工酶的比较研究

用4.5％聚丙烯酰胺凝胶平板电泳研究了异育淇鲫及其母本淇鲫和父本兴国红鲤的肌可溶性蛋白以及肾、肝、眼、背白肌和心等五种组织的乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)和酯酶(EST)。结果发现:异育淇鲫的肌可溶性蛋白以及同工酶的电泳图谱与母本淇鲫相同而与父本兴国红鲤显著不同,因而认为异育淇鲫是淇鲫雌核发育的产物,父本基因对子代基本无影响。在此基础上,本文对异源精子在雌核发育中所起的生物学作用进行了初步探讨。     

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.