两温度梯度多重PCR鉴别牛早期胚胎性别的技术

稳定、可靠和快速的牛胚胎性别鉴定方法在生产应用中具有重要意义.通过两温度梯度PCR方法对牛基因组、克隆胚胎、胚胎样品进行性别鉴别实验研究,建立了稳定、简便、快速的牛早期胚胎性别鉴别两温度梯度PCR方法,鉴定时间仅为57分钟.采用两温度梯度PCR方法对30枚奶牛胚胎进行了早期性别鉴别,并将鉴别的15枚胚胎(11枚为雌性,4枚为雄性)移植到同期处理的15头受体母牛体内.60天后妊娠检查,有7个受体成功受孕,5头受体怀孕晚期流产,流产犊牛全部为母犊.结果产下1公1母两头犊牛,流产个体与出生个体的性别与PCR鉴别结果完全相符.     

两温度梯度多重PCR鉴别牛早期胚胎性别的技术研究

稳定、可靠和快速的牛胚胎性别鉴定方法在生产应用中具有重要意义。通过两温度梯度PCR方法对牛基因组、克隆胚胎、胚胎样品进行性别鉴别实验研究,建立了稳定、简便、快速的牛早期胚胎性别鉴别两温度梯度PCR方法,鉴定时间仅为57分钟。采用两温度梯度PCR方法对30枚奶牛胚胎进行了早期性别鉴别,并将鉴别的15枚胚胎（11枚为雌性,4枚为雄性）移植到同期处理的15头受体母牛体内。60天后妊娠检查,有7个受体成功受孕,5头受体怀孕晚期流产,流产犊牛全部为母犊。结果产下1公1母两头犊牛,流产个体与出生个体的性别与PCR鉴别结果完全相符。      

间接免疫荧光法鉴别小鼠早期胚胎性别的研究

以间接免疫荧光法检测昆明系小鼠早期胚胎雄性特异性H—Y抗原的表达。结果表明:54%的胚胎为H—Y阳性(雄性);46%为H—Y阴性(雌性)。经与昆明系小鼠的自然性比率(♂:52%;♀:48%)比较,两者无显著性差异。 经细胞遗传学方法确证,以免疫荧光法鉴别的胚胎性别,雄性的鉴别准确率为75.50%;雌性为82.97%。 本文还就影响鉴别准确率的若干因素以及本方法在生产中的应用前景等问题进行了分析讨论。     

精子性别化对奶牛控制的试验

本试验获得牛犊雌性控制率达81．8％（Table1）。十头母牛产犊十一头：二雄,九雄,其中一头产异性双犊。于1．08－1．10蔗糖密度梯度之间,可以清楚地观察到Y精子能被荧光素染色（Table2);H－Y抗血清处理改变Y精子的荧光染爸,说明对Y精子有抑制作用（Table3)。制备有一定纯度和效价的H－Y抗血精IgG用以性别化处理精子;通过人工受精技术、使母牛得到受处理的精子而正常受胎。本试验结果对奶牛性别控制的前景是美好的。     

云南省奶牛胚胎移植试验

实验用12头黑白花奶牛（3-9岁）,PGF[2α]作同步发情处理后,周期第10-12天,总剂量36 mg的FSH-P按递减方式每日肌肉注射2次,间隔12小时,共注射4天,在第3天加注PGF[2α]35 mg,进行超数排卵处理。12头供体牛共得胚135枚,可用胚数118枚,为总胚数的87.47%。平均每头得胚11.25枚。胚胎分别移植给20头同步发情处理的黑白花奶牛和20头黄牛受体（有3头为自然发情）,每头移植1枚胚胎。结果,奶牛受孕率为35%（受孕7头,产犊7头）;黄牛受孕率为40%（受孕8头,流产2头,产犊6头）。奶牛和黄牛总受孕率为37.5%。     

奶（黄）牛卵母细胞体外受精及体外发育的研究

自屠宰场获得150头淘汰黑白花奶牛和19头黄牛的卵巢,取得优、良级卵母细胞2060枚,采用两种培养液(A.B.)和三种不同试剂(Aa、Ba、Bb),对解冻牛精子获能(capacitation)。在38.5℃和相对湿度为100％的5％CO_2箱中进行成熟、受精、发育培养至196小时,其结果表明A液所获得的效果优于B液,但差异不显著;Aa试剂获能优于Bb,差异显著。共获得桑椹胚和囊胚58枚、非手术移植10头牛16次,三头妊娠,其中二头受体在妊娠二月半月后返情,外阴流血,确认为胚胎早期死亡,一头受体妊娠产犊,于1990年4月10日产公犊1头,体长87公分、身高78公分、体重29公斤、妊娠284天,正常分娩。(移植天为0天)。     

体细胞核移植生产转ω-3脂肪酸去饱和酶基因sFat-1克隆猪

转ω-3脂肪酸去饱和酶基因猪在优质猪培育及研究ω-3不饱和脂肪酸预防心血管和癌症疾病中的作用方面有着重大的应用．本研究首次通过体细胞核移植制备了转线虫ω-3脂肪酸去饱和酶基因sFat-1猪．将sFat—1基因转染到大白猪胎儿成纤维细胞,获得转基因阳性细胞克隆,然后以转基因细胞为核供体、体外成熟的猪卵母细胞为核受体构建克隆胚胎,胚胎体外培养或进行移植．先后移植了1889枚1-4细胞期克隆胚胎到10头受体母猪的输卵管内,28天B超检测9头受体母猪妊娠（90％）,7头妊娠足月（70％）分娩产下21头仔猪,体细胞克隆猪的效率为1．1％（出生仔猪／移植胚胎）．体细胞克隆猪效率的提高,主要是对克隆胚胎的移植环节进行了改进,比较了受体母猪排卵状况对胚胎移植效率的影响．当受体母猪卵泡发育处于即将排卵或正在排卵阶段,能够获得较高的妊娠率和妊娠足月率（100％）,而排卵后移植妊娠足月率为0％．对健康存活15头克隆猪进行了PCR和Southern检测,证实13头为转基因猪,转基因阳性率为87％．RT—PCR检测13头转基因猪,12头表达sFat—1基因．以上结果表明,利用优化的体细胞转基因结合核移植技术,可以成功地批量生产转sFat-1基因的克隆猪．     

运用PCR对小鼠植入前胚胎进行性别诊断

根据C57BL6小鼠Y染色体重复序列145C5的碱基顺序,设计并合成一对引物,运用PCR扩增昆明白小鼠入前胚胎卵裂球DNA,以确定其性别,共对108枚活检胚胎的相应卵裂球进行了性别诊断,获雄性胚46枚,雌性胚62枚,移植后分别获雄性仔鼠4只,准确率100％（4／4）,雌性仔鼠9只,准确率70％（9／13）,本研究结果表明小鼠Y染色体重复序列145C5的碱基顺序在C57BL6小鼠和昆明白小鼠中基本一致,为农牧业动物进行性别选择和运用PCR进行单基因病植入前遗传学诊断提供了方法学基础。     

我国动物学家取得试管水牛性别控制成果

2月13日上午11点20分,在广西水牛研究所的一头杂交母水牛,通过分离XY精子性别控制产下了雌性水牛双犊。据悉,这在世界尚属首例。据介绍,这两头性控试管水牛犊体重均为29kg。“姊妹花”出生经历了复杂、严密的科学设计:首先,用流式细胞仪分离出良种摩拉水牛精液的X精子和Y精子;然后, 将X精子与本地母牛的卵母细胞进行体外受精生产性别控制的胚胎;最后将3枚雌性胚胎移植给一头受体母牛,经10月怀胎后生产出来。该项由国家自然科学基金、广西壮族自治区人民政府主席基金、自治区科技厅科技攻关项目资金联合资助的水牛性别控制研究项目由卢克焕教授主持,广西水牛研究所和广西畜禽品种改良站共同参与完成。该项成果的关键技术是分离XY 精子技术。这意味着水牛生公生母完全可能人为控制。     

试管牛和试管羊胚胎性别的鉴定

奶牛和山羊的卵母细胞经过体外成熟、体外受精和体外发育至桑椹期,在显微操作下,吸取4～6个胚胎细胞,应用巢式PCR技术对其DNA进行SRY基因的测定以进行胚胎性别鉴定。共有27枚转有外源基因的试管牛胚胎和207枚转基因试管羊胚胎进行了SRY基因检测。选取10枚经过性别鉴定的牛胚胎移植于8头受体母牛和124枚已知性别的羊胚胎移植于44头受体母羊,移植后妊娠率分别为37．5％（牛,3/8）和61．4％（羊,27/44）。最后产生1头分娩牛犊和2头流产胎牛以及14头分娩羊羔和2头流产胎羊,它们的性别与胚胎性别鉴定的结果完全相符。 Abstract: The oocytes of bovines and goats were subjected to in vitro maturation,in vitro fertilization(IVF)and in vitro development upto morula stage．4～6 embryonic cells were aspirated with micro-manipulating and the embryo sexes were identified by detecting SRY gene with nested PCR procedure．A total of 27 transgenic IVF bovine and 207 transgenic IVF goat embryos were performed SRY gene detection．10 bovine and 124 goat sexed embryos were selected to be transferred into 8 bovine and 44 goat recipients,respectively,leading to the pregnant rates of 37．5％( in bovine,3/8)and 61．4％(in goat,27/44)．In the end,1 cattle and 14 goatlets were born at term but 2 fetal bovine and 2 fetal goats were miscarried．Their sexes were fully in accordance with the embryonic sex predetermination．     

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.