Comparison of the Value of Pulsed-field Gel Electrophoresis,Random Amplified Polymorphic DNA and Amplified rDNA Restriction Analysis for Subtyping Taylorella equigenitalis

Eight strains of Taylorella equigenitalis were identified by a polymerase chain reaction using a primer pair specific to the 16S rDNA of T equigenitalis. These eight strains were chosen because they had previously been shown to represent eight distinct genotypes by pulsed-field gel electrophoresis analysis after separate digestion of the genomic DNA with ApaI or NotI. The eight strains could be classified into six or seven types by random amplified polymorphic DNA analysis using different kinds of primers. Amplified rDNA restriction analysis after separate digestion with five restriction enzymes, including AluI and MboI, of the 1,500 bp fragments of rDNA amplified by polymerase chain reaction did not discriminate the genomic variations among the eight strains of T equigenitalis. Thus, pulsed-field gel electrophoresis was shown to discriminate these eight organisms better than random amplified polymorphic DNA analysis, while amplified rDNA restriction analysis was found to be unsuitable for subtyping T equigenitalis.     

Demonstration of Heterogeneous Genotypes of Taylorella equigenitalis Isolated from Horses in Six European Countries by Pulsed-Field Gel Electrophoresis

Forty-six isolates of Taylorella equigenitalis were analysed by pulsed-field gel electrophoresis (PFGE) after separate digestion of the genomic DNA with ApaI and with NotI. The isolates had been obtained from horses in six European countries and were classified into 18 genotypes. In Belgium, 2 genotypes were detected in 2 isolates, in England 9 among 15, in Finland 2 in 2, in France 2 among 10, in Sweden 3 among 5, and in Switzerland 3 among 12. Two English isolates and 4 French isolates gave identical PFGE profiles to those of Kentucky 188 from the United States. A common genotype was found in 5 isolates from Belgium and England and also in 10 isolates from France and Switzerland. The analysis of genomic DNA from 12 isolates of T. equigenitalis obtained from male horses in France, Sweden and Switzerland gave no evidence of a sex-related difference in the genomic DNA. Genomic DNA from 11 streptomycin (STM)-susceptible isolates obtained in Sweden and Switzerland were classified into four genotypes by PFGE. Each of the six genotypes determined among the 17 isolates from these two countries had single phenotypes for resistance or susceptibility to STM.     

增强猪传染性胸膜肺炎灭活苗对小鼠保护力的研究

为了提高猪传染性胸膜肺炎灭活苗的保护力,本研究利用基因重组技术表达了猪传染性胸膜肺炎放线杆菌6种主要致病因子蛋白:rApxⅠ、rApxⅡ、rApxⅢ、rApxⅣ、rApfa和rOMP。设立试验Ⅰ组(灭活苗),试验Ⅱ组(灭活苗、rApxⅠ、rApxⅡ、rApxⅢ和rOMP),试验Ⅲ组(灭活苗、rApxⅠ、rApxⅡ、rApxⅢ和rApxⅣ),试验Ⅳ组(灭活苗、rApxⅠ、rApxⅡ、rApxⅢ和rApfa)和空白对照组(PBS),每组26只BALB/c小鼠,分3次免疫,每次间隔2周,每周检测血清抗体水平,在免疫后第2周、第4周和第5周,MTT法检测脾脏T细胞增殖水平及ELISA法测定IFN-γ分泌水平。在第3次免疫后的第7 d,将每组剩余20只小鼠平均分成2组,分别以APP1型菌(5×10~9 CFU)和APP7型菌(1×10~(11) CFU)进行攻毒保护试验。结果表明,向灭活苗中添加重组亚单位成份可以提高机体的细胞免疫和体液免疫水平,并能提高灭活苗的交叉保护率;试验Ⅱ组的ApxⅠ和OMP抗体水平以及细胞免疫水平均显著高于其它各组(p<0.05),对于APP1和APP7型菌的攻毒也提供了明显优于其它各组的保护结果,试验Ⅲ、Ⅳ组的细胞、体液免疫水平及保护率较试验Ⅰ组也有所提高。结果显示出ApxⅠ、OMP抗体水平和细胞免疫水平与攻毒保护率之间存在着正相关性,向灭活苗中加入重组蛋白成份可以提高疫苗的交叉保护,试验Ⅱ组通过激活体液免疫和细胞免疫,对两个血清型APP的攻击提供了很好的保护作用,从而为猪传染性胸膜肺炎新型疫苗的研制提供参考。     

聚肌胞对山羊传染性脓疱皮炎治疗效果的研究

[目的]研究聚肌胞对山羊传染性脓疱皮炎的治疗效果。[方法]设试验组、药物对照组、空白对照组对自然感染传染性脓疱皮炎初期的羔羊进行治疗并观察。[结果]试验组羔羊与2个对照组比较,好转快,好转率高。[结论]聚肌胞用于山羊传染性脓疱皮炎治疗可以提高疗效,缩短疗程。     

高粱苗期病害分布型研究初报

高粱苗期病害主要是由立枯丝核菌(Rhizoctonia solani)AG—5引起的土壤传染病害,该病害的病原菌土下分布状况可以通过病株、病斑的分布型间接地测定。病株为随机分布,而病斑则属于核心分布,但也符合负二项分布.病株分布型反映土内病菌的随机存在,病斑分布型则主要反映了病菌在土内接种势能的不均一分布(聚集分布)。以上结果为在病害调查中确定取样方式与样本大小提供了理论基础。     

武陵地区山羊传染性胸膜肺炎的药物防治研究

为预防和控制武陵山地区山羊传染性胸膜肺炎,采用4种药物对该区山羊进行了体内预防试验和治疗试验,结果表明:泰妙菌素和红霉素对山羊传染性胸膜肺炎霉形体感染具有预防作用,且泰妙菌素和红霉素预防效果最好,环丙沙星、四环素预防作用可靠性差;用4种药物对山羊传染性胸膜肺炎自然病例和人工病例做治疗及增重试验,结果表明:与对照组相比,环丙沙星组,四环素组差异显著,增重较明显,泰妙菌素组和红霉素组差异极显著,增重非常明显。     

Development of an Indirect Enzyme-Linked Immunosorbent Assay for Seromonitoring Contagious Bovine Pleuropneumonia Using Recombinant Lipoprotein LppQ of Mycoplasma mycoides subsp mycoides SC as Antigen

Mycoplasma mycoides subsp mycoides SC （MmmSC） is the etiological agent of contagious bovine pleuropneumonia （CBPP）. The lipoprotein LppQ encoded by lppQ gene is specific to MmmSC and is found in the type strain and in field strains isolated in Europe, Africa, and Australia, as well as in vaccine strains. No serological cross-reactions were observed with the related mycoplasmas of the Mycoplasma mycoides cluster. The N-terminal domain of the mature lipoprotein LppQ is hydrophilic, and it induces a strong, specific, early, and persistent immune response in naturally and experimentally infected animals. Mycoplasma-specific TGA （Trp） codons are utilized as stop codons in most other organisms. The lppQ N-terminal fragment from MmmSC HVRI X strain, the Chinese strain for CF antigen production, was mutated with one-step overlapping extension PCR. Sequence analysis confirmed the successful mutation from A to G in codon 198 in the lppQ gene. The fragment containing the mutation site was subcloned into the pET32a expression vector. The recombinant protein with molecular weight of 42 kDa was purified using the Ni-NTA His.Bind purification kit, with a purity of up to 95%. Western blot indicated that the standard positive serum of CBPP could react with the recombinant protein. The purified protein was diluted to 0.35 μg mL^-1, and coated to microtiter enzyme-linked immunosorbent assay （ELISA） plates. Indirect ELISA reaction conditions were optimized. The value of P/N was determined to be 4.8 （0.934/0.193）, the sensitivity to be 95.8% （46/48）, and the specificity to be 98.9% （161/163）. 3 817 cattle serum samples from three different provinces were detected by the indirect ELISA and CFT. The Kappa value is 0.63, which is middle or high agreement between the two methods.     

羊传染性脓疮皮炎治疗

羊传染性脓痂皮炎又被称为羊传染性脓疱病、羊口疮病,是由羊传染性脓疱病毒感染引发的一种急性接触性传染性疾病。羊养殖主产区均有发生,是一种常见疾病。羊传染性脓痂皮炎虽然造成的死亡率较低,但是会严重影响羊群正常采食,造成营养物质供给不足,身体逐渐消瘦,抵抗能力变差,易继发感染多种传染性疾病,表现出复杂的临床症状,威胁羊群健康。