Counter current line absorption immunoelectrophoresis in an alternative diagnostic screening test to counter current immunoelectrophoresis in Aleutian disease (AD) eradication programs

Counter current immunoelectrophoresis (CCIE) is the diagnostic method used in the ongoing Aleutian disease virus eradication program on Danish mink farms. There has been an increasing demand for an alternative diagnostic test especially to evaluate suspected false positive CCIE reactions. We compared test results of a number of negative and positive mink sera in indirect counter current immunoelectrophoresis (ICCIE), counter current line absorption immunoelectrophoresis (CCLAIE) and radio immuno assay (RIA) with test results from counter current immunoelectrophoresis and found that counter current line absorption immunoelectrophoresis is the best alternative diagnostic screening test to counter current immunoelectrophoresis for Aleutian disease eradication programs. Not only proved the CCLAIE test to be useful for evaluation of doubtfully positive CCIE reactions, but it was found to have a higher sensitivity than the CCIE test.     

聚合酶链反应检测猪细小病毒的研究

本研究成功地建立了检测猪细小病毒（ＰＰＶ）的聚合酶链反应（ＰＣＲ）技术。以１６个核苷酸引物对首次完成了ＰＰＶＤＮＡ结构蛋白ＶＰ１编码区２２８ｂｐ片段的扩增。同样数目的另一引物对，也成功扩增了Ｖｐ２编码区１５８ｂｐＤＮＡ片段。ＰＰＶＢＭ－１株与其它国内分离株（广西株、天津株和哈尔滨株）均出现相同扩增结果。琼脂糖凝胶电泳显示了特异条带（ＶＰ１２２８ｂｐ．Ｖｐ２１５８ｂｐ），而伪狂犬病病毒、犬细小病毒均未扩增，表明了本方法的特异性。同时，限制性内切酶分析（Ｖｐ１２２８ｂｐ及Ｖｐ２１５８ｂｐ分别含单一ＰｖｕⅡ、ＥｃｏＲⅠ位点），也证实了特异性。本方法敏感性高，可检出１０ｆｇ模板ＤＮＡ。既可作样品的快速检测，又能检查细胞系的污染。具有特异、简便、快速的优点。     

用地高辛标记核酸探针检测鹅细小病毒的研究

从带有鹅细小病毒(GPV)NSI基因的重组质粒pMD18T-NS1用限制性内切酶EcoRI和BamH1双酶切回收1880bp大小片段,并制备出地高辛标记的GPV核酸探针。其标记效率达到0．01pg／μl。特异性检测结果表明,该探针能与GPV不同毒株核酸发生特异性杂交,而与对照的DPV、GPPV等病毒的核酸杂交反应均为阴性;敏感性检测结果表明,该探针对GPV的最低检出量为0．0224pg。该探针对不同方法处理的GPV感染病料进行检测,均出现杂交阳性。表明所研制的标记探针用于GPV的检测足可行的。     

猪繁殖与呼吸综合征病毒的研究进展

从遗传变异、检测以及宿主免疫3个方面,对近年来在猪繁殖与呼吸综合征病毒(PRRSV)方面的研究进行简要综述。     

猪细小病毒和猪圆环病毒2型多重PCR检测方法的建立与应用

根据GenBank中已发表的猪细小病毒(PPV)和猪圆环病毒2型(PCV2)基因序列,对各病毒基因区进行同源性分析,确定PPV的VP2和PCV2的ORF2基因为各病毒的诊断靶序列,设计特异性引物,在建立各病毒单项PCR技术的基础上,优化多重PCR反应条件,建立了2种病毒的多重PCR技术,可同时扩增PPV的313 bp和PCV2的447 bp的特异性片段。用多重PCR技术与单项PCR技术对比检测试验证明二者的总符合率为100%。表明建立的多重PCR检测方法,具有特异、快速、准确的特点,可同时鉴别诊断这2种病毒。从10个发病猪场和门诊病例的病猪采集的211份样品,用山西省农科院畜牧兽医研究所动物基础医学研究课题组研究的多重PCR检测方法,检出猪圆环病毒2型阳性56份,阳性率为27%;猪细小病毒病阳性42份,阳性率为20%;二者混合感染17份,阳性率为8%。这为掌握山西这2种病毒的感染情况提供了依据。     

猪Ghrelin基因真核表达载体构建(英文)

[目的]为研究转生长相关基因对猪的作用。[方法]采用RT-PCR方法,从13/17罗伯逊易位杂合子猪小肠组织中提取总RNA,将其纯化后作为PCR扩增模板,参考GenBank公布的猪Ghrelin的mRNA序列设计合成具有Nhe I和Hind III双酶切位点引物,扩增获得Ghrelin基因cD-NA全长序列。将准确的Ghrelin基因片段克隆于 pMD19-T simple Vector后进行序列分析,获得猪Ghrelin基因cDNA全长基因片段。经Nhe I和Hind III双酶切,将 Ghrelin基因cDNA片段连接到真核表达载体pEGFP-N1,获得真核表达载体的重组质粒pEGFP-Ghrelin。重组质粒转染猪成纤维细胞,观察标记基因荧光蛋白的表达。[结果]13/17罗伯逊易位杂合子猪的Ghrelin基因与已发表的序列相同,并成功获得具备猪Ghrelin基因全长cDNA序列的真核表达载体pEGFP-Ghrelin。[结论]构建的真核表达载体可以用于转基因猪的进一步试验,同时也为研究Ghrelin的调节机制奠定基础。     

类猪圆环病毒因子P1核酸链型和极性的研究

研究报道类猪圆环病毒因子P1的核酸链型和极性的研究结果。采用氯化铯平衡密度梯度离心获得较为纯净的病毒粒子后,提取病毒DNA,经S1核酸酶消化、特异性单引物第一轮PCR扩增结合常规第二轮PCR扩增等研究,结果表明,类猪圆环病毒因子P1为单股、负链基因组。     

CB·氨基酸在猪卵母细胞孤雌激活及体外培养中的作用

[目的]研究CB、氨基酸在猪卵母细胞孤雌激活及体外培养体系中的作用,为优化相关技术体系提供依据。[方法]卵母细胞经体外成熟培养,采用不同孤雌激活方法(Ele.+CB组、CB组、Ele.组、对照组),研究CB在激活中的作用。激活后采用PZM3培养液,并去除氨基酸成分,探索氨基酸对体外培养胚胎的作用。[结果]CB+Ele.组的卵裂率显著地高于其他3组(P<0.05),囊胚率为32.7%,囊胚细胞数为61.4,而其他3组均未出现囊胚。电激活(脉冲电压100 V/mm,脉冲时程100μs,脉冲次数1次)联合CB处理,可激活卵母细胞体外发育至囊胚,CB有助于提高卵裂率、囊胚率。添加氨基酸的培养液中的卵母细胞的卵裂率、囊胚率、囊胚细胞数显著提高(P<0.05),表明氨基酸能提高猪孤雌激活胚胎培养效果。[结论]添加CB、氨基酸在猪卵母细胞孤雌激活及体外培养体系中能提高胚胎的培养效果。     

Detection of porcine circovirus genotypes 2a and 2b in aborted foetuses from infected swine herds in the State of S?o Paulo,Brazil

Background

Porcine circovirus type 2 (PCV2) has been associated with several disease complexes, including reproductive failure. The aim of this study was to identify the subtypes of PCV2 that are associated with reproductive failure in pigs from the State of São Paulo, Brazil and to investigate co-infections with other infectious organisms.

Findings

Samples of 168 aborted foetuses or mummified foetuses from five farrow-to-finish swine farms known to be infected with PCV2 and located in the State of São Paulo were tested for PCV2 by polymerase chain reaction (PCR). Positive samples were additionally tested for porcine parvovirus (PPV), Leptospira spp. and Brucella spp. by PCR. PCV2 was detected in 18 of the samples (10.7%). PPV, Brucella spp. and Leptospira spp were found in 2, 10 and 0 cases, respectively. Eleven PCV2 strains were sequenced and determined to be either genotype 2a (n = 1) or 2b (n = 10).

Conclusions

The findings indicate that the frequency of PCV2 infections in aborted porcine foetuses from the State of São Paulo is rather low (10.7%) and that co-infection with other pathogens is common and may be involved in PCV2 associated reproductive failure. No repeatable, characteristic amino acid motifs for regions of the PCV2 capsid protein seemed to be associated with abortion in sows.