错位双链RNA,丙氧鸟苷和原核细胞DNA促旋酶B对鸭乙肝病毒的抑制作用

人工合成错位双链ＲＮＡ（ａｍｐｌｉｇｅｎ）是一种已知的干扰素诱导剂。单独和／或与其它抗病毒药物联合使用治疗鸭乙型肝炎病毒（ＤＨＢＶ）阳性鸭。这些药物包括丙氧鸟苷（ｇａｎｃｉｃｌｏｖｉｒ）和原核细胞ＤＮＡ促旋酶Ｂ抑制物（ｃｏｕｍｅｒｍｙｃｉｎＡｌ）。单独和／或联合该两种药物时,对鸭血清和肝组织内ＤＨＢＶ均有抑制作用,但以三种药物联合时抑制效果最好。上述下种方案治疗结束后肝内松弛环状ＤＮＡ（ＲＣ）和超螺旋ＤＮＡ（ＳＣ）持续存在,而且不能消除血中鸭乙肝表面抗原（ＤＨＢｓＡｇ）。对治疗的大多数鸭血清干扰素,测定结果表明,ａｍｐｌｉｇｅｎ能诱生鸭干扰素,但其出现时间与抗病毒效果产生没有平行关系。本研究为人慢性乙型肝炎治疗合理使用抗病毒药物和免疫诱导剂提供了参考。     

[卡其].肯拜尔鸭和北京鸭胰脏和胰管的比较解剖

本研究共观察[卡其]·肯拜尔鸭(Khaki Campbell)45只,北京鸭[Pekin duck(Anas domestica L.)]41只,比较了两种鸭胰叶和胰管的形态结构。结果如下:[卡其]·肯拜尔鸭和北京鸭的胰脏都分为背侧胰叶,腹侧胰叶和脾胰叶。除有背侧胰管和腹侧胰管外,还观察到自背侧胰叶尾端发出另一胰管入十二指肠,并命名为第一胰管。[卡其]·肯拜尔鸭和北京鸭的背侧和腹侧胰管入肠类型均可分为三种:背、腹侧胰管以左、右向排列;背侧胰管在前,腹侧胰管在后;腹侧胰管在前,背侧胰管在后。此外,[卡其]·肯拜尔鸭出现多条胰管入肠的例数多于北京鸭。     

表达猪圆环病毒2型Cap蛋白的重组猪瘟兔化弱毒疫苗株的构建与鉴定

猪瘟(CSF)是由猪瘟病毒(CSFV)引起的一种毁灭性传染病,给养猪业造成重大经济损失。猪瘟兔化弱毒疫苗(C株)是一株非常安全、有效的优秀弱毒疫苗,对各年龄和品种的猪都极其安全,同时对不同基因亚型的CSFV均能提供有效的免疫保护。在现地,CSFV和猪圆环病毒2型(PCV2)混合感染的现象时常发生,有必要研制针对这两种病毒混合感染的二价疫苗。本研究首次构建了表达PCV2 Cap蛋白的重组C株,并评价了其在体内外的特性。结果表明,该重组病毒与C株具有相近的体外增殖特征,能够稳定表达Cap蛋白,在家兔体内具有与C株相似的生物学表型,在免疫家兔后10 d,抗CSFV E2抗体全部转阳,然而抗Cap抗体未能转阳。本研究为进一步优化表达PCV2Cap蛋白的重组C株奠定了基础。     

安徽庐江鸭乙型肝炎病毒LJ-76转染细胞系的建立

为建立鸭乙型肝炎病毒ＬＪ－７６的转染细胞系,将ＬＪ－７６病毒ＤＮＡ插入到ｐＵＣ１９的ＥｃｏＲⅠ位点上,分离得到含有双拷贝ＬＪ－７６ＤＮＡ的重组质粒．通过磷酸钙沉淀方法,将经ＣｓＣｌ等密度离心纯化的ＬＪ－７６ＤＮＡ双体导入到人肝癌细胞ＢＥＬ７４０２中．收集转染细胞的培养液进行蔗糖密度梯度离心,所得沉淀经检测发现含有ＬＪ－７６ＤＮＡ并具有特异性ＤＨＢＶ内源性ＤＮＡ多聚酶活性;对上述样品通过ＤｏｔＥＩＡ检测ＤＨＢＶ核心抗原及表面抗原结果为阳性．Ｓｏｕｔｈｅｒｎｂｌｏｔ分析表明转染细胞内存在病毒ＤＮＡ复制中间体ｃｃｃＤＮＡ、ｓｓＤＮＡ和ｒｃＤＮＡ,而ｃｃｃＤＮＡ被认为是复制活动较为活跃的标志．电镜观察转染细胞的上清发现有病毒颗粒的存在．     

Changes at the ecto-mesodermal interface during development of the duck preen gland

Summary An ultrastructural investigation of the organogenesis of the duck preen gland showed variations at the ecto-mesodermal interface in the course of development. During the period of invagination, ectoderm and mesoderm were separated by a continuous basal lamina. Morphogenesis of the tubules is characterized by a preferential deposition of non-oriented collagen fibres localized at the branching sites. Direct contacts between ectodermal extensions and mesodermal cells, through gaps in the basal lamina, appeared at the end-buds after the morphogenetic pattern was established and before the onset of the glandular secretory activity. The correlation between the modification of the ecto-mesodermal interface and the differentiation of uropygial ectoderm is discussed.     

猪圆环病毒2型新疆株全基因组的滚环扩增与序列分析

滚环扩增技术是一种体外恒温DNA扩增方法,特异性好,敏感性强,已广泛应用于微生物学领域。首先采用鉴别PCR对来自新疆某地区的5份猪病料进行猪圆环病毒2型的检测,接着对检出的2份猪圆环病毒2型阳性DNA样品进行滚环扩增。滚环扩增产物经单一限制性内切酶(SacⅡ)酶切及琼脂糖凝胶电泳鉴定,结果显示2份样品都出现了猪圆环病毒2型基因组大小的条带。对目的条带进行回收、克隆与测序,结果表明2株新疆株猪圆环病毒2型的全基因组大小皆为1768bp。遗传进化分析显示2株的基因型为PCV2a和PCV2e。     

Complete nucleotide sequence of a novel porcine circovirus-like agent and its infectivity in vitro

A novel agent (hence termed as P2) was isolated from pig sera in China, which contained covalently bound circular genomic DNAs of 993 nucleotides. Sequence analyses indicated that the agent was closely related to the porcine circovirus (PCV). The molecular clone of P2 was constructed subsequently and used for the following studies. Intracytoplasmic inclusions and intranuclear inclusions were only found in PK-15 cells transfected with the tandem dimer of P2 molecular DNA clone. Intracytoplasmic inclusions were round or irregular in shape and 0.1-0.4 μm in diameter, and intranuclear inclusions were electronically denser than intracytoplasmic inclusions and had two general shapes: round/small (0.1 μm in diameter) and hexagonal/large (0.5―1.4 μm in diameter). The inclusions were not membranously bound. The cells transfected with the tandem dimer of P2 molecular DNA clone were tested positive for P2 DNA at passages 5. The P2 antigen could be detected in both transfected and passaged PK-15 cells. This is the first report regarding the complete nucleotide sequence of a small DNA genome in a circovirus-like infectious agent in vitro.     

鸡鸭异种间嵌合体的制备

本研究采集孵化14期鸡胚血液中的原始生殖细胞,在液氮中冷冻保存三个月后,解冻成活率达80％以上。以Ficoll密度梯度离心将其从血液中分离纯化,分离获得纯度为27.5%,平均每枚胚胎可获得近50个PGCs。将分离的PGCs 100-200个以微注射法转移至15期早期麻鸭胚胎中制备了鸡鸭种间嵌合体,孵出8（6♂,2♀）只雏鸭,总孵化率为7.3%（8／110）。以鸡W染色体特异性DNA探针原位杂交法在早期鸭胚性腺中检测鸡PGCs。在被检测的21个鸭胚的性腺中,16个有不同程度的阳性信号,嵌合率达76.2%(16/21)。实验结果表明鸡原始生殖细胞能够迁移并定居到鸭胚性腺中,并有可能在鸭性腺中增殖分化成有功能的配子。