雏番鸭细小病毒病快速诊断方法的建立

番鸭三周病、番鸭细小病毒型“白点病”以及番鸭小鹅瘟在临床上发病日龄非常相似,也是各个养鸭场经常出现的疾病,它们有时会出现混合感染或继发感染,给诊断带来了困难。针对这种情况,本文通过对三周病病原、番鸭细小病毒型“白点病”病原以及番鸭小鹅瘟病原核酸的分析比较,在三周病病原的特异性区域设计了一对特异性引物,通过PCR检测,能够快速、准确的诊断出雏番鸭细小病毒病。     

羊痘研究概况

羊痘病毒基因组庞大,约有150 kb,包括中间编码区和两端相同的反向末端重复序列;绵羊痘病毒和山羊痘病毒基因组彼此十分相似,约有96%的核苷酸完全相同.p32蛋白是目前世界各地分离鉴定的所有羊痘病毒株共有的且特异性很强的结构蛋白,在诊断和预防方面具有重要的应用价值.虽然羊疸从临床症状和宿主特异性上很客易做出诊断,但进一步的实验室确诊还是必要的,现已有多种检测方法和诊断试剂.控制该病最有效的方法是使用疫苗对易感动物进行免疫接种.文章从病原学、诊断和预防控制等方面对羊痘进行综述.     

梨果实贮藏中可溶性果胶和半纤维素分子结构的变化

 为了了解分子结构变化与耐藏性的关系，以耐贮性不同的苹果梨和新高梨为试材，利用Ultrogel AcA 22凝胶柱渗漏分离，比较了梨贮藏中可溶性果胶和半纤维素分子大小的变化。结果表明，苹果梨的半纤维素分子大于新高梨。在贮藏过程中，耐贮性强的苹果梨果实可溶性果胶分子大小变化不明显，但半纤维素分子明显变小。相反，新高梨的可溶性果胶分子明显变小，而未观察到半纤维素分子大小的变化。说明梨的耐贮性与可溶性果胶分子结构变化及半纤维素分子大小有关，而与半纤维素分子结构变化没有直接关系。     

桑天牛卵啮小蜂孤雌生殖及体内沃尔巴克氏体(Wolbachia)的检测

桑天牛卵啮小蜂(Aprostocetus prolixus)有孤雌生殖现象,其后代几乎为雄性。沃尔巴克氏体(Wolbachia)是广泛分布于节肢动物体内的一类共生菌,参与多种调控寄主的生殖活动机制。通过对外膜蛋白基因(wsp)、细菌细胞分裂蛋白基因(ftsZ)和核糖体16S rDNA基因的特异性扩增,在米蛾(Corcyra cephalonica Stainton)的DNA中分别扩增出约600、1000和900 bp的片断,验证了米蛾体内已感染了Wolbachia;而在桑天牛卵啮小蜂的DNA中未扩增出任何片断,表明Wolbachia在桑天牛卵啮小蜂体内未被感染或感染率极低。     

Molecular characterization and genetic relationship among almond cultivars assessed by RAPD and SSR markers

RAPDs and SSRs were used to study the genetic diversity of Iranian almond cultivars and their relationship to important foreign cultivars and three related species. Eight unidentified almond Shahrodi cultivars and three wild almonds (Prunus communis, Prunus orientalis and Prunus scoparia) were also included. Of the primers tested, 42 (out of 80) RAPD and 18 (out of 26) SSR primers were selected for their reproducibility and high polymorphism. A total of 664 polymorphic RAPD bands were detected out of 729 bands. The number of presumed alleles revealed by the SSR analysis ranged from 3 to 10 alleles per locus with a mean value of 6.64 alleles per locus. Both techniques discriminated the genotypes very effectively, but only RAPDs were able to discriminate the cultivars Monagha and Sefied. Results demonstrated an extensive genetic variability within the tested cultivars as well as the value of SSR markers developed in peach for characterization of almond and related species of Prunus. Dice similarity coefficient was calculated for all pair wise comparisons and was used to construct a UPGMA dendrogram. For both markers a high similarity in dendrogram topologies was obtained although some differences were observed. All dendrograms, including that obtained by the combined use of both the marker data, depicted the phenetic relationships among the cultivars and species, depending upon their geographic region and/or pedigree information. Almond cultivars clustered with accession of P. communis showing their close relationship. P. orientalis and P. scoparia were clustered out of the rest of P. dulcis.     

湖北和安徽省油菜病毒病调查和病毒血清鉴定

2003年秋至2005年春2个油菜生长季分别到湖北和安徽2省12县市油菜产区进行病毒病发病情况调查,除局部地区和地块发病率达到20%～40%,多数大面积油菜发病率在0.1%以下。应用间接酶联免疫吸附法检测258份病害样品,TuMV占样品总数的90.7%,CMV占样品总数的8.9%,ORMV占样品总数的0.8%。     

Bluetongue virus serotypes 1 and 3 infection in Poll Dorset sheep

Objective To study the clinical signs following bluetongue virus serotypes 1 and 3 infection in Poll Dorset sheep.
Design A clinical and pathological study.
Procedure Twenty Poll Dorset sheep were inoculated with bluetongue virus serotypes 1 or 3, each inoculum having a different passage history. The sheep were examined daily and their clinical appearance and rectal temperatures recorded. Heparinised and non-heparinised blood samples were taken at intervals for virological and serological study. Gross pathological findings were recorded for several sheep at necropsy and tissue samples were collected from three sheep for virological studies.
Results All inoculated sheep developed clinical disease. The clinical signs and gross pathological changes varied considerably but were consistent with damage to the vascular endothelial system. There was a decline in the titres of infectious bluetongue virus and of antigen in tissues collected between 7 and 12 days after infection.
Conclusions The severity of disease was related to the speed of onset and duration of pyrexia and not the development or titre of viraemia. Generally, those animals with sensitive mouths, depression, coronitis, recumbency and reluctance to move were the most debilitated. Whole blood was the most reliable source of infectious virus from acutely and chronically infected and convalescent animals. However, tissue samples particularly spleen, collected from dead or killed animals suffering from either peracute or acute forms of disease were most appropriate for the rapid confirmation of a clinical diagnosis.     

A Possible Correlation between the Blood Leukocyte Formula and the Use of Glucocorticoids as Growth Promoters in Beef Cattle

Clinical analyses designed to set welfare parameters were performed on blood drawn from the caudal vein of 14 groups of cattle (young bulls and heifers) (n = 10) from 480 to 550 kg b.w., each group representative of a different farm. The leukocyte formula exhibited a lymphocytopenia in four groups compared with the values from a control group (n = 50). This finding was related to the possible illicit use of corticoids as growth promoters in meat production. The individual plasmas tested negative by two different ELISA kits for corticosteroids, but chemical analyses by LC-MS/APCI (detection limit 0.5 ng/ml) on the pooled plasma of each of the 14 groups revealed the presence of beclomethasone and fluocinolone acetonide in 3 of the 4 suspect farms. These corticosteroids are not always efficiently screened by commercially available immunoassays. The epidemiological reliability of blood analysis as a screening test for such drugs is discussed in the light of the need for quality certification of the whole meat production processes from farm to fork, and for enhanced animal welfare.     

Detection of challenge virus in fetal tissues by nested PCR as a test of the potency of a porcine parvovirus vaccine

To estimate the potency of a porcine parvovirus (PPV) vaccine, three vaccinated and three non-vaccinated pregnant gilts were infected with PPV and the distribution of the virus was studied in the tissues of their 51 fetuses. Virus detection was attempted using haemagglutination (HA) and immunofluorescence (IF) assays, as well as by standard (single) and nested polymerase chain reactions (PCR). None of the detection methods yielded positive results when used to test for the presence of virus in suspensions of organs from the fetuses from the vaccinated gilts. However, the virus was detected in the fetuses from non-vaccinated gilts as follows: HA was positive in 14 cases out of 23 (60.8%), IF in 16/23 (69.5%), standard PCR in 12/20 (60%), and the nested PCR in 19/23 (82.6%). Although the correlation among the results of various methods of virus detection was rather close (r<0.83), the sensitivity of the nested PCR was the highest, both when testing dilutions of PPV and when analysing the fetal organs. The nested PCR therefore provides a reliable approach for studies of virus distribution in fetal organs, with special reference to potency tests on vaccines.     

Kinetics of Interferon-Gamma Production and its Comparison with Anti-Listeriolysin O Detection in Experimental Bovine Listeriosis

The kinetics of the production of interferon gamma (IFN-) in whole blood culture and its comparison with anti-listeriolysin O (ALLO) detection by ELISA were studied during oral infection of calves with Listeria monocytogenes. Culture filtrate antigen (CFA), listeriolysin O (LLO), and sonicated antigen (SA) were used to prime the peripheral blood mononuclear cells (PBMCs) and the plasma from orally infected calves. IFN- and ALLO appeared as early as day 7 of an oral infection. IFN- was detected earlier with LLO than with SA. The Max50 interleukin (IL-2) activity and IFN- estimated in the culture supernatant from PBMCs primed in vitro with different antigens of L. monocytogenes revealed high induction of IL-2 and IFN- by CFA, LLO and live antigen. IFN- assay and ALLO detection were used for testing cases of repeat breeding in dairy cattle. It appeared that detection of IFN- employing LLO can be used to diagnose listerial infections.