区别鹅细小病毒和番鸭细小病毒的PCR-RFLP方法的建立

根据GenBank登录的鹅细小病毒（GPV）和番鸭细小病毒（MDPV）非结构蛋白（NS）基因特征,本研究设计1对特异性引物对GPV和MDPV基因组DNA进行PCR扩增,目的片段大小均为810 bp,并对PCR产物进行切胶回收。用EcoRⅠ酶对GPV和MDPV特异性胶回收产物进行酶切鉴定,结果显示MDPV经EcoRⅠ酶切后琼脂糖凝胶电泳检测片段为2段,大小为530和280 bp;而GPV经EcoRⅠ酶切后琼脂糖凝胶电泳检测片段大小不变。本研究建立了一种快速区别GPV和MDPV感染的检测方法,可对番鸭感染水禽细小病毒的情况进行快速鉴别诊断。     

腐蹄病C型节瘤拟杆菌纤毛蛋白基因的克隆与表达载体的构建

用PCR技术从腐蹄病C型节瘤拟杆菌克隆出具有免疫保护性抗原0.85kb纤毛蛋白基因（pili基因），利用该基因构建了纤毛蛋白基因表达载体。提取C型节瘤拟杆菌染色体DNA；用所设计的专一性引物进行PCR，扩增出pili基因；将pili基因克隆于TE载体，TE－pili重组质粒pili基因序列测定结果正确，用EcoRI酶切，低熔点胶回收pili基因片段，经klenow补平后，用T4DNA连接酶将其与中间载体pPLλ连接，将pili基因克隆于pPLλ载体，经BamHI、BamHI HindⅢ、Dral酶切鉴定pili基因正向插入pPLλ载体；扩增pPLλ-pili重组质粒，用BamHI酶切出2.1kb大小片段，回收后，与PME290表达质粒连接，转化宿主细胞PAK／2pfs中，对获得的重组质粒用BamHI酶切，出现2.1kb大小的带,证明含有目的基因。     

铜绿假单胞菌oprH基因DNA疫苗的构建与检测

研究旨在构建铜绿假单胞菌oprH基因的DNA疫苗。试验根据GenBank中已发表的铜绿假单胞菌的oprH基因序列,设计合成了一对特异性引物,利用PCR技术由铜绿假单胞菌基因组DNA中扩增获得该目的基因,进行胶回收纯化并与T载体进行连接,经双酶切和PCR鉴定后将重组质粒进行酶切回收目的基因片段,并将其亚克隆于真核表达载体pCAGGS-HA中,以双酶切和PCR方法进行鉴定。结果显示：PCR成功扩增出约600 bp的oprH基因,连接T载体后的重组质粒经双酶切和PCR鉴定,均可获得大小正确的目的基因片段。真核重组载体鉴定结果显示,oprH基因成功克隆于真核表达载体pCAGGS-HA中。研究表明,试验成功构建了oprH基因的DNA疫苗,为进一步研究其免疫效果及铜绿假单胞菌新型疫苗的研制提供参考。     

家蝇基因组文库的构建

从孵化 36 h的蝇蛆中提取基因组 DNA,用限制性内切酶 Bcl 随机酶切 ,回收 10～ 2 3kb的酶切 DNA片段 ,通过匹配粘性末端与磷酸化的 EMBL3Bam H 酶切载体臂连接 ,在体外经包装系统包装成活的重组噬菌体 ,成功地构建了家蝇基因组文库。重组噬菌体转染 KW2 51 宿主菌 ,测定文库效价为 5× 10 4 pfu/m L     

犬新孢子虫NcSRS2基因原核表达质粒的构建

根据已发表的犬新孢子虫NcSRS2基因序列,设计1对含有EcoRⅠ和NotⅠ酶切位点的引物。以提取犬新孢子虫虫体基因组DNA为模板,应用PCR扩增获得NcSRS2 ORF基因片段,将此基因片段克隆到pMD18-T Simple载体上,用EcoRⅠ和NotⅠ双酶切该片段,回收得到含有两个酶切位点黏端的Nc-SRS2 ORF基因,将此基因片段克隆至相同酶切回收后的PGEM-4T-2原核表达载体中,获得重组质粒pGEX-NcSRS2,经PCR鉴定,限制性内切酶分析和克隆片段序列测定比较,证实了重组质粒的正确性。     

绵羊白细胞介素2基因的克隆与表达载体构建

从绵羊血中分离白细胞,提取绵羊白细胞RNA,利用RT-PCR、PCR扩增绵羊白细胞介素2(OvineIL-2)基因。将OvineIL-2PCR产物与TE载体定向连接,用SaLI和BamHI双酶切重组TE,利用低溶点胶回收500bp大小的片段;将其补平后与PPSD质粒连接,用EcoRI酶切鉴定,找出正向连接重组质粒。用BamHI酶切重组PPSD质粒,低熔点胶回收2500bp大小的片段;将其与经BamHI酶切去磷酸化的PME290表达质粒连接,筛选出阳性重组PME290,即为OvineIL-2基因表达载体。     

SREBP-1c基因重组腺病毒的构建及其在犊牛原代肝细胞中的表达

将携带有化学合成的SREBP-1c基因的质粒先用Xba Ⅰ酶切,Klenow补平突出末端,纯化回收后再用Hind Ⅲ酶切,切胶回收目的基因片段;并将其克隆至用EcoR Ⅴ/HindⅢ酶切回收的pShuttle-EGFP-CMV(-)TEMP穿梭载体上.经酶切鉴定后,重组穿梭质粒和腺病毒pAdxsi质粒分别用I-Ceu Ⅰ+I-Sce Ⅰ双酶切处理,T4DNA连接酶连接,获得重组质粒pAdxsi-GFP-SREBP1c,酶切鉴定后经Pac Ⅰ酶切线性化转染HEK293细胞,经包装扩增后用TCID50测定病毒滴度.以重组腺病毒感染犊牛原代肝细胞,采用qRT-PCR和Western blot检测细胞中SREBP1c mRNA和蛋白的表达量.结果显示,重组腺病毒酶切鉴定正确,滴度可达1.2×1010,腺病毒感染犊牛原代肝细胞中SREBP-1c mRNA和蛋白的表达显著升高.结果表明,本试验成功构建了SREBP-1c基因过表达重组腺病毒,且SREBP-1c在犊牛原代肝细胞中高度表达.     

产植酸酶黑曲霉菌株S8的基因扩增与鉴定

本文主要报道了用 3种不同方法从S8黑曲霉菌丝体中提取基因组DNA ,最适方法是经改进的Vitagene试剂盒法。PCR扩增效果最好的是设计时没有去掉phyA基因内含子的引物 ,获得的特异性PCR产物长约 1.5kb。同时对PCR反应体系进行了优化。对扩增出的目的片段用 3种不同方法进行纯化回收 ,结果是PCRFragmentRe coveryKit法回收效果最好 ,其产量可达到约 10ng/ μL。根据已报道的植酸酶phyA基因序列酶切位点 ,对回收的目的片段进行酶切鉴定 ,该基因能被BamHⅠ、SalⅠ酶切 ,不能被HindⅢ、XbalⅠ、KPnⅠ酶切 ,与已知的phyA基因酶切图谱基本一致 ,进一步判定PCR扩增产物中含有植酸酶phyA基因目的片段     

家蚕微孢子虫诊断新技术的研究

为了正确诊断家蚕微孢子虫(Nosema bobycis, N.b),共征集了11种微孢子虫作为诊断的材料。根据N.b.孢子(日本株)的DNA序列,设计一对引物,以N.b.DNA为模板进行PCR扩增得到一个约317bp的片段,将此片段克隆到大肠杆菌DH5 α中,提取重组质粒、酶切、回收目的片段,经地高辛标记为探针,对N.b.等11种微孢子虫DNA进行核酸杂交检测,只有N.b.DNA呈阳性反应。检测灵敏度均达到1ng DNA水平。     

一株偶发分支杆菌基因组文库的构建

对一株致病性的非结核分支杆菌(NTM)即偶发分支杆菌(M.fortuitum)建立基因组文库,选用同尾酶Sau3 A I和BamH I分别酶切基因组DNA和载体pUC18,回收1 kb～7 kb大小范围的插入性DNA片段,与已经酶切去磷酸化的载体用T4连接酶连接,并转化入DH5а感受态细胞中,进行蓝白斑和氨苄抗性筛选,...     

多枝赖草高分子量核DNA的有效制备

以多枝赖草Leymus multicaulis黄化苗幼嫩叶片为材料,在液氮中研磨成粉末,加入冰冷的细胞核抽提缓冲液,经一系列钢制细胞筛过滤,离心分离细胞核,相差显微镜镜检后,用低熔点琼脂糖包埋,蛋白酶K原位裂解,经脉冲场电泳分离,用1%低熔点琼脂糖回收获得了较纯净的分子量大于2 Mb的核DNA,Southern杂交显示没有叶绿体和线粒体DNA的污染.利用该方法制备的高分子量核DNA,可用于后续可转化人工染色体(TAC)文库的构建和基因组分析.     

低分子质量左聚糖对人体肠道菌群调节作用

采用三氯乙酸(trichloroacetic acid,TCA)法除去Paenibacillus bovis sp.nov BD3526来源的高分子质量左聚糖中蛋白质的同时制备得到低分子质量左聚糖,并用离子交换层析法对低分子质量左聚糖进行分离纯化,用凝胶渗透色谱(gel permeation chromatography,GPC)法测定纯化后样品的分子质量及其分布,用核磁共振(nuclear magnetic resonance,NMR)仪和傅里叶变换红外光谱(fourier transform infrared spectrometer,FT-IR)表征其化学结构,用原子力显微镜(atomic force microscope,AFM)表征其在水溶液中的构象,最后采用荷兰应用科学研究(The Netherlands Organization For Applied Scientific Research,TNO)组织建立的体外筛选平台评价其对人体肠道菌群的调节作用.体外实验结果表明,此低分子质量左聚糖能促进双歧杆菌特别是婴儿双歧杆菌和长双歧杆菌的增殖,其促进作用优于低聚果糖(fructooligosaccharide,FOS).     

旋毛虫各隔离种嗜酸性粒细胞变化的研究

旋毛虫各隔离种感染猪后,其血液中嗜酸性粒细胞显著增多,而其它各类细胞无明显变化,嗜酸性粒细胞于感染后７ｄ开始升高,１６ｄ左右达最高峰,以后逐渐下降趋势;猪旋毛虫和旋毛形线虫的嗜酸性粒细胞数量始终高于犬旋毛虫和本地毛形线虫,嗜酸性粒细胞增多可作为早期诊断旋毛虫病的重要临床指标之一。     

奶牛朊病毒基因克隆与序列分析

根据已报道正常牛朊蛋白(PrP^c)基因(PRNP)序列设计引物，采用PCR法扩增了6头荷斯坦奶牛的PRNP基因，将其克隆到T-Vector。序列测定及分析表明所克隆的奶牛PRNP基因片段为795bp，该基因内无内含子，包含了牛PRNP完整编码区序列，编码264个氨基酸的前体蛋白，推测其分子量约34ku。其中2头共同含有未曾报道的牛PRNP多态性位点M120I，无义突变G234A，但未引起酶切位点变异，未发现插入或缺失变异；与已报道牛PRNP序列(GenBank收录号为DI0613)相比，两者核苷酸序列同源性为99％，其编码的氨基酸同源性为99％。     

In vivo morphological and antigenic characteristics of Photobacterium damselae subsp. piscicida

The present study was conducted to examine the morphology and antigenicity of Photobacterium damselae subsp. piscicida by culturing the bacterium in vivo in the peritoneal cavity of sea bass (Dicentrarchus labrax) within dialysis bags with either a low molecular weight (LMW) cut-off of 25 kDa or a high molecular weight (HMW) cut-off of 300 kDa. Differences were observed in the growth rate between the bacteria cultured in vivo or in vitro. Bacteria cultured in vivo were smaller and produced a capsular layer, which was more prominent in bacteria cultured in the HMW bag. Antigenicity was examined by Western blot analysis using sera from sea bass injected with live Ph. d. subsp. piscicida. The sera recognised bands at 45 and 20 kDa in bacteria cultured in vivo in the LMW bag. Bacteria cultured in vivo in the HMW bag did not express the 45 kDa band when whole cell extracts were examined, although the antigen was present in their extracellular products. In addition, these bacteria had a band at 18 kDa rather than 20 kDa. Differences in glycoprotein were also evident between bacteria cultured in vitro and in vivo. Bacteria cultured in vitro in LMW and HMW bags displayed a single 26 kDa band. Bacteria cultured in the LMW bag in vivo displayed bands at 26 and 27 kDa, while bacteria cultured in vivo in the HMW bag possessed only the 27 kDa band. These bands may represent sialic acid. The significance of the changes observed in the bacterium''s structure and antigenicity when cultured in vivo is discussed.     

牛白细胞介素2基因原核表达及多克隆抗体制备

根据GenBank发表的牛白细胞介素2(BoIL-2)基因序列,设计1对特异性引物,应用RT-PCR技术扩增出重组牛白细胞介素2(rBoIL-2)基因。将克隆片段与pMD18-T载体连接,并经过酶切及PCR鉴定,测序结果显示,克隆的BoIL-2基因与GenBank发表的BoIL-2基因序列同源性为98.7%。将测序正确的克隆片段与pET30a(+)载体连接,构建重组表达质粒pET30a(+)-rBoIL-2,通过双酶切及PCR鉴定阳性的重组质粒进行序列测定后在大肠杆菌的表达,分子质量约为23.49 ku;表达产物主要分布在包涵体中。Western blotting证实所得到的重组蛋白为BoIL-2重组蛋白。用镍离子亲和树脂对所得的BoIL-2重组蛋白进行纯化,并免疫新西兰兔成功制备兔抗rBoIL-2多克隆抗体,为下阶段的研究提供了重要的试验材料。     

Chromosomal DNA probes for the identification of asaccharolytic anaerobic pigmented bacterial rods from the oral cavity of cats.

A dot-blot hybridisation assay using isolated high molecular weight DNA as whole chromosomal probes of the cat pigmented asaccharolytic Bacteroides/Porphyromonas species was used against both purified high molecular weight DNA and DNA released on membranes from whole cells for the identification of B. salivosus and for its differentiation from the other anaerobic species isolated from normal and diseased mouths of cats and horses. 32P-labelled probes were compared with digoxigenin (DIG)-labelled probes (Boehringer-Mannheim). The whole chromosomal probes were specific--differentiating B. salivosus from a variety of species (including members of the genera Bacteroides, Fusobacterium, Eubacterium, and Prevotella) found in normal and abnormal mouths of cats and horses. Likewise, asaccharolytic black pigmented Group 2 strains were distinguishable from all strains tested. However, cat strains of P. gingivalis which show 68-76% DNA-DNA homology with human strain P. gingivalis ATCC 33277T, were not distinguishable from each other using either 32P-labelled or DIG-labelled probes. The minimum amount of pure Bacteroides DNA which could be detected by the 32P-labelled probe was 100-300 pg, while the amount of pure DNA detected by the DIG system was 1-3 mg after room temperature colour development for 1 h and 100-300 pg after 6 h colour development.     

Distinct adiponectin profiles might contribute to differences in susceptibility to type 2 diabetes in dogs and humans

Dogs develop obesity-associated insulin resistance but not type 2 diabetes mellitus. Low adiponectin is associated with progression to type 2 diabetes in obese humans. The aims of this study were to compare total and high molecular weight (HMW) adiponectin and the ratio of HMW to total adiponectin (S_A) between dogs and humans and to examine whether total or HMW adiponectin or both are associated with insulin resistance in naturally occurring obese dogs. We compared adiponectin profiles between 10 lean dogs and 10 lean humans and between 6 lean dogs and 6 age- and sex-matched, client-owned obese dogs. Total adiponectin was measured with assays validated in each species. We measured S_A with velocity centrifugation on sucrose gradients. The effect of total and HMW adiponectin concentrations on MINMOD-estimated insulin sensitivity was assessed with linear regression. Lean dogs had total and HMW adiponectin concentrations three to four times higher than lean humans (total: dogs 32 ± 5.6 mg/L, humans 10 ± 1.3 mg/L, P<0.001; HMW: dogs 25 ± 4.5 mg/L, humans 6 ± 1.3 mg/L, P<0.001) and a higher S_A (dogs: 0.78 ± 0.05; humans: 0.54 ± 0.08, P = 0.002). Adiponectin concentrations and S_A were not lower in obese dogs (0.76 ± 0.05 in both groups; P=1). Total adiponectin, HMW adiponectin, and S_A were not associated with insulin sensitivity in dogs. We propose that differences in adiponectin profiles between humans and dogs might contribute to the propensity of humans but not dogs to develop type 2 diabetes. Dogs with chronic, naturally occurring obesity do not have selectively reduced HMW adiponectin, and adiponectin does not appear to be important in the development of canine obesity-associated insulin resistance.     

广西巴马小型猪IFN-Y基因的克隆和序列分析

将猪外周淋巴细胞进行体外培养,在刀豆球蛋白A(conA)刺激培养15h后,提取培养淋巴细胞总RNA,应用RT-PCR技术扩增广西巴马小型猪Y-干扰素(IFN-Y)基因,并克隆到PMD18-T载体上,进行测序。测序结果表明,扩增的cDNA全长558个碱基,包含501个碱基开放阅读框架,编码166个氨基酸,分子量为19．42ku。此cDNA与人、牛、山羊、马、狗和鼠的IFN-Y基因核苷酸比较,同源性分别为74．9％,86．5％,86．9％,81％,58．7％和63．3％,与其它猪种的IFN-Y基因核苷酸比较同源性为100％。     

五个品种(系)鸡的RAPD亲缘关系分析

本试验用DNA池法从40条随机引物中筛选出29条多态性、重复性好的引物,对贵州黄鸡、兴黔黄鸡、乌骨鸡三个培育品种(系)和地方品种兴义矮脚鸡及引进选育品种矮脚黄鸡共五个品种(系)进行随机扩增多态亲缘关系分析。结果表明,29条引物共扩增出稳定、清晰、重复性好的条带190条,其中多态性片段127条,在300bp￣3000bp之间。单个引物扩增出的RAPD条带在4￣13条之间,平均为6.55条。五个品种(系)间的亲缘关系符合它们的育种背景[1,2,3]。