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关键词： 稀土元素   代谢   作用机理   生物学效应  

摘要： 结合近来国内外有关稀土元素的研究进展情况 ,本文现就其在动物体内的代谢。

关键词： 线粒体假基因   进化生物学  

摘要： 在真菌、昆虫、无脊椎动物和脊椎动物等许多分类单元中 ,都已发现mtDNA序列的核转座现象。在PCR扩增时 ,往往同时扩增出mtDNA和细胞核中线粒体假基因 (Numts) ,Numts混淆系统发育和群体遗传研究 ,得出错误的结果。本文综述了Numts的检查和避免的方法 ,以及在进化生物学研究中的应用进展。

关键词： 分子生物学技术   水产动物疾病   免疫学诊断技术   核酸诊断技术   核酸技术  

摘要： 近年来,分子生物技术在水产养殖疾病诊断上得以广泛应用。根据目前国内外研究的动向,对免疫检测技术、核酸检测技术、核酸技术与免疫学相结合方法等进行了综述,详细阐明了各个技术的原理、特点及应用。病原体的提纯是应用这些方法的主要困难。

关键词： 钼   生物学功能   动物生产   营养   中毒   分布   吸收   代谢   饲料添加剂  

摘要： 分别从营养学和中毒学角度论述了钼在饲料及动物机体内的分布、吸收、代谢规律,从酶学的观点阐述了钼在动物体内的生物学作用及钼的营养与中毒的机制;钼除与酶有关外,与日粮中的铜、硫、钨等元素关系密切;动物钼缺乏或过量,与人和动物的多种疾病有关。

关键词： 朊病毒   表位   传染性海绵状脑病   基因  

摘要： 朊病毒(Prion)可引起的人和动物的传染性海绵状脑病(Transmissible\nSpongiform Encephalopathies,TSE<,s>).该致病因子具有与普通病原微生物不同的理化和生物学特性,至今其致病机理尚不完全明确.该研究利用基因克隆表达和生物信息学技术,结合病理组织学及实时荧光定量RT-PCR(Real-time RT-PCR)等方法,在对PrP<\'c>功能表位分析的基础上,对其主要结构蛋白合成肽的免疫学特性进行了分析,并对PrP<\'c>重组蛋白脑内接种金黄地鼠的生物学特性进行了探索,为今后进一步研究Prion的致病机理和检测技术奠定了基础,研究内容如下:1.分别成功克隆了奶牛、牦牛、大熊猫、恒河猴、孔雀及珍珠鸡的PrP<\'c>基因,运用分子生物学软件对其和相关种属PrP<\'c>基因及氨基酸序列进行了序列比较、遗传进化和同源性分析,对PrP<\'c>结构蛋白的功能表位及二级结构进行了预测,获得了有关种属间PrP<\'c>基因结构多态性及功能表位生物学信息,为PRNP基因多态性与朊病毒病的连锁关系研究提供了基础数据.2.利用Goldenkey分子生物学软件分析确定了奶牛PrP<\'c>的抗原功能表位,化学合成特定序列结构蛋白多肽,经鉴定后按照一定的分子比与载体蛋白匙孔嘁血蓝蛋白偶联,经检测后制备牛PrP<\'c>多肽兔多抗,并进行了免疫学特性检测.结果表明,所制备的特定表位结构蛋白多肽抗体经ELISA方法测定抗体效价达1:10<\'8>,经Western blotting试验检测,能够与PrP<\'c>重组结构蛋白和纯化的牛PrP<\'c>结合.提示该结构蛋白多肽抗体具有良好的免疫学特性,有望用于TSE检测试剂的研制.3.采用原核表达系统对牛PrP<\'c>结构蛋白进行了成功表达,并利用结构蛋白多肽抗体进行了鉴定.结果表明:在37℃、OD为0.8时经IPTG(1.0mmol/L)诱导表达3h条件下,重组PrP<\'c>蛋白的表达量最高.经Western blotting方法检测,表达蛋白与多肽抗体反应性良好.结果提示:该研究成功制备了牛PrP<\'c>重组结构蛋白,该蛋白有望进一步用作Prion结构生物学的研究材料.4.为了弄清PrP<\'c>重组结构蛋白的生物致病性及其对PrP<\'c>基因表达的影响等生物学特性,进而为研究PrP<\'c>转化为PrP<\'sc>的选择压力条件提供生物学检测方法奠定基础.对试验组6只金黄地鼠脑内注射纯化后的PrP<\'c>重组结构蛋白(10μg/μl,3μl),对照组2只金黄地鼠用磷酸盐缓冲液(PBS)同法处理,临床观察记录;102天后将实验动物经眼球静脉放血处死,分别取小脑、脑干(Obex部件)、大部分大脑经甲醛固定、制作石蜡切片、H.E.染色,光镜下进行组织病理学观察;取另一部分大脑提取总RNA利用实时荧光定量RT-PCR方法检测不同处理组金黄地鼠PrP<\'c>表达差异.结果表明:金黄地鼠脑内注射102天内,未见异常临床症状,试验组与对照组无明显差异;未见异常组织病理学变化;试验组和对照组金黄地鼠脑组织PrP<\'c>基因表达无显著差异.结果提示:通过PrP<\'c>重组蛋白在检测时间内未能引起地鼠脑组织海绵状病理变化,未能引起PrP<\'c>mRNA表达水平改变,为进一步研究PrP<\'c>重组蛋白结构生物学提供了基础数据.

关键词： Gene Expression   Milk Proteins   Proto-Oncogene Proteins   Animals   Blotting   Western   Cell Adhesion   Cells   Cultured   Comparative Study   DNA Primers   DNA-Binding Proteins   Genetic Vectors   Green Fluorescent Proteins   Luminescent Proteins   Mice   Protein-Tyrosine Kinase   Receptors   Erythropoietin   Research Support   Non-U.S. Gov't   Retroviridae   Ribosomes   Trans-Activators   Transduction   Genetic  

摘要： Stable expression of cloned genes in mammalian cells has been achieved in the past by retroviral transduction using bicistronic retroviral vectors. In these vectors, the use of an Internal Ribosome Entry Site (IRES) allows simultaneous expression of a protein of interest and a fluorescence marker. However, traditional cDNA cloning in these vectors is often difficult. Here we report the construction of a high-throughput retroviral vector using the Invitrogen "Gateway" Cloning system. The Gateway recombination sequences (attR) flanking the ccdB and chloramphenicol resistance genes were incorporated at the 59 of the IRES of pMX-IRES-GFP, -CD2, or -CD4 vectors. Through recombination, these vectors can acquire cDNAs coding for genes of interest, which will result in simultaneous expression of the recombined gene and the marker protein. We constructed Gateway bicistronic vectors coding for the erythropoietin receptor (EpoR) and GFP, CD4, or CD2. Epo-dependent proliferation assays and analysis of Jak2-dependent EpoR cell-surface expression showed that these vectors were able to function indistinguishable from the original pMX-EpoR-IRES-GFP. The expression levels of the genes cloned upstream the IRES were proportional to the levels of expression of GFP, which was cloned downstream of the IRES. We used the same approach and generated Ba/F3 cells that overexpress STAT5a, STAT5b, or a constitutively active form of STAT5. Overexpression of STAT5 lead to a significant effect on the intrinsic adherence to plastic of these cells, but did not change their proliferative responses to cytokines. We discuss possible applications of the new vectors for cell signaling and expression cloning.

关键词： 禽痘病毒   分子生物学   哺乳动物   非复性型载体   动物病毒表达载体   多价重组病毒疫苗  

摘要： 禽痘病毒(AvipoXvirus)是痘病毒科的成员,可以作为病毒载体表达外源基因。近年来禽痘病毒作为非复制型栽体的应用已成为国内外研究的热点,成功地构建了表达不同外源基因的重组禽痘病毒,在肿瘤疾病和艾滋病的预防和治疗中都有不俗的表现。文章主要对禽痘病毒的分子生物学特性及其在哺乳动物中的应用作了概述。

关键词： POPULATION biology   CRUSTACEA   AMPHIPODA   BIOMASS   PLANT biomass   COHORT analysis  

摘要： Seasonal population dynamics of the gammarid Acanthostepheia malmgreni Goees in Conception Bay, Newfoundland, were examined from October 1998 to November 2000. This species exhibited a 2.5-year life span, with the reproductive cycle correlating with seasonal phytoplankton flux. Females were semelparous and died following a 5-month brooding period and the subsequent release of juveniles in April and May. The biennial life cycle of this population should result in the presence of two cohorts in the hyperbenthos at any given time. However, the cohorts alternated in strength from year to year, which affected annual density, biomass and production during the study period. Densities were 64 plus or minus 87 ind. per 100 m super(3) in 1999 and 491 plus or minus 492 ind. per 100 m super(3) (mean plus or minus SD) in 2000. Secondary production was estimated at 18-44 mg C m super(-2) in 1999 and 180-311 mg C m super(-2) in 2000. The annual P/ B ratios were 0.89 and 2.27 in 1999 and 2000, respectively. Growth varied both among and within cohorts, with different life-history stages exhibiting variable growth rates ranging from 0 to 12 mg dry mass month super(-1).

关键词： Trypanosoma cruzi   Changes' disease   Echimiyidae   Trichomys apereoides   histopathology   ethylene diamine tetra acetic acid  

摘要： To understand the interaction of Trypanosoma cruzi with caviomorph rodents, which supposedly have an ancient co-evolutionary history with this parasite, experimental infection of laboratory reared Trichomys apereoides with several isolates of both genotypes of the parasite was studied. Parasitemia, pattern of hematic cells, specific humoral immune response, histopathological features and parasite clearance were appraised. T. apereoides maintained stable infections independent of the T cruzi genotype as demonstrated by positive PCR results in analyses of several tissues after a 5 months follow-up. The acute phase was characterized by abundant and disseminated presence of amastigotes, vacuolization and/or myocytolysis. Lymphocytosis was a common feature. The chronic phase was characterized mainly by lymphomacroeosinophilic infiltrates independent of the inoculated T cruzi isolate. T cruzi of different genotypes did not show any tissular preference in T apereoides. (C) 2004 Elsevier Inc. All rights reserved.

关键词： POPULATION biology   CRUSTACEA   BIOMASS   LIFE sciences   PHYTOPLANKTON   MYSIDAE  

摘要： Seasonal population dynamics of Mysis mixta Lilljeborg were studied from December 1998 to November 2000 at a 240 m deep site in Conception Bay, Newfoundland. At this depth, temperature was <0degreesC and salinity between 32.0 and 34.0 psu year-round. The spring phytoplankton bloom began in early or late March and reached a maximum in late April to mid-May. M. mixta exhibited a highly synchronised life cycle, with spawning and mating occurring in October to November, embryos brooded for similar to5 months, and juveniles released during spring bloom sedimentation in April and May. Females were semelparous and died at age 2.5 years, following release of juveniles in spring, whereas the majority of mature males died at age 2 years, following mating in November. The biennial life cycle of this population resulted in the presence of two cohorts in the hyperbenthos at any given time. Variation in density and biomass was low among cohorts but high within cohorts, the latter probably due to the high motility of mysids. Densities in 1999 and 2000 were 242+/-379 and 544+/-987 ind. per 100 m(3) (mean+/-SD), respectively. Although growth rates were similar between years, rates measured from changes in dry mass differed both seasonally and among life-history stages (range from -4 to 7 mg month(-1)). Annual secondary production was estimated at 29-73 mg C m(-2) in 1999 and 53-205 mg C m(-2) in 2000. The annual P/B ratios were 1.62 and 1.19 in 1999 and 2000, respectively.