T-2毒素毒性作用研究进展

T-2是A类单端孢霉烯族化合物中毒性最强的一种,对动物机体具有较强的危害,可造成多个系统出现中毒效应。作者主要对T-2毒素对动物的广泛毒性作用进行论述,且对下一步的研究方向进行了展望。     

Cloning and Sequence Analysis of Major Histocompatibility Complex Ⅰ Gene from Goose F1 of Fast-growth Lines

According to the multiple alignments identified major histocompatibility complex Ⅰ (MHC Ⅰ) gene conserved sequence registered in GenBank from the family ducks (Anatidae) anser waterfowl, a pairs of specific primers for the fragments of MHCⅠgene of goose F1 from fast-growth lines were designed and synthesized by Primer Premier 5.0. Using the genome DNA of goose F1 from fast-growth lines, the target gene fragment was obtained by PCR. To conduct sequencing of the fragments of MHCⅠgene of goose F1 from fast-growth lines and make sequence alignment and analysis of protein structure and function by bioinformatics, and research the characteristics of MHCⅠgene of goose F1 and the physicochemical properties of the protein. Bioinformatics was analyzed the nucleic acid data, deduced amino acid sequence and phylogenetic trees. The result of sequence analysis showed that the fragments of MHCⅠgene of goose F1 from fast-growth lines was 1036 bp in length, which coded 96 amino acids polyprotein. The homology were 93% and 83% with MHC Ⅰ gene and coding sequence of Wulong goose in NCBI respectively. There were 72 different bases sequence and 16 amino acids change. There also was higher homology with other poultry, and existed genetic relationship of Siji goose > chickens > ducks.The homology segment sequences corresponding to the fragments of MHCⅠ gene of goose F1 coded 96 amino acids protein, which molecular weight, PI, positively or negatively charged amino acid, estimated half-life, instability index, aliphatic index and average hydrophobicity were 11.342 ku, 5.32, 14, 17, 2.8 h, 34.92, 42.81, -1.066, respectively, and appeared 9 B cell epitopes, but contained no signal peptide. These results indicated that the protein for hydrophilic non-secreted proteins, had the high immunogenicity. In addition, The protein structure study indicated that alpha-helix, beta-sheet, beta-turn and random coil were 31.25%,16.67%, 14.58% and 37.50%, respectively. There existed amino terminal domain and carboxyl terminal domain in the tertiary structure. Therefore, MHC gene had significant difference between species and populations of individuals by the pathogen pressure in environment, and there were the interaction between polymorphism of MHC molecules and the diversity of antigenic peptide. MHC determined the differences of individual susceptibility to disease, and could be treated as a candidate gene for disease resistance.     

广东省部分猪场细环病毒感染状况

细环病毒（TTV）目前在全世界的猪群中广泛存在。为了调查其在广东省猪群流行情况,我们运用PCR方法对广东省不同地方猪场和散养户送检的445份血清进行了检测。结果表明：TTV总的阳性率为68.1%（303/445）,其中TTV1阳性率为43.1%（192/445）,TTV2阳性率为24.9%（111/445）。TTV1的阳性率高于TTV2的阳性率,且猪场送检样品阳性率高于散养户。TTV1和TTV2存在混合感染,猪场样品混合阳性率为23.1%（88/381）,散养户样品混合阳性率为1.6%（1/64）。几份阳性样品测序和进化分析显示,它们分别属于TTV1和TTV2。调查结果表明TTV在广东猪群中已经广泛存在。     

布鲁菌S2疫苗株免疫牛与牛种、羊种布鲁菌自然感染牛ELISA鉴别诊断方法的建立

为建立区分猪种布鲁菌S2疫苗株接种奶牛与布鲁菌自然感染奶牛,BLAST比对分析羊种、牛种、猪种、犬种、沙林鼠种和绵羊种6种布鲁菌基因序列,发现repA—related基因是猪种布鲁菌与牛种及羊种布鲁菌的差异基因。设计引物PCR扩增获得repA-related基因片段,克隆并原核表达得到了布鲁菌repA—related融合蛋白,以repArelated蛋白建立间接EI．IsA检测方法。用repA—related蛋白间接ELISA检测猪种s2疫苗株接种动物血清为阳性,检测牛种和羊种布鲁菌自然感染动物血清为阴性。repA—related蛋白间接EusA能从试管凝聚实验（SAT）及常规ELIsA检测阳性的奶牛血清样本中,区分出s2疫苗接种牛与牛种布鲁菌感染牛。     

Influence of recombinant duck follistatin protein on embryonic muscle development and gene expressions

Follistatin (FST) acts as a positive regulator of muscle development by inhibiting the activities and expression of myostatin. The recombinant duck FST protein was injected into hatching eggs and was also added to the medium of duck myoblast to study its role on duck embryonic muscle development and gene expressions. Duck embryo weight increased 3.49% (p > 0.05) in FST treatment group as compared with control group, but minor effects were found on leg or breast muscle weights of ducklings at 2 days post‐hatching (p > 0.05). Relative expression of Pax7 was upregulated in both leg and breast muscle tissues (p < 0.05), while MyoD was only upregulated in leg muscle (p < 0.05), and Myf5 was only upregulated in breast muscle (p < 0.05). Relative expression of myostatin was downregulated in both muscle tissues researched (p < 0.05). In vitro studies also showed some maker genes relevant to protein synthesis and degradation, cells’ proliferation and differentiation had significant changes in myoblasts after treated with FST. These results suggested that in ovo feeding of recombinant FST protein to duck hatching eggs had an effect on duck embryo development but have less roles on the duck embryonic muscle development.     

Evaluation of a new strategy to modulate skeletal development in racehorses by imposing track-based exercise during growth: the effects on 2- and 3-year-old racing careers

REASON FOR PERFORMING STUDY: No data exist on the effects of conditioning exercise at foal age on workload and subsequent clinical injury rate during their 2- and 3-year-old racing careers. OBJECTIVES: To investigate the effects of subjecting TB foals to conditioning exercise prior to the start of race training on: the workload required to reach a level of fitness sufficient to compete; and the prevalence of orthopaedic injury during the first 2 seasons of their racing careers. METHODS: Twenty 18-month-old TBs, 12 subjected to conditioning exercise at foal age (CONDEX) and 8 exercised spontaneously at pasture only (PASTEX) were trained and entered in competitive events. Workload was quantified using the cumulative workload index (the product of average velocity and distance at a specific gait) and the animals were monitored clinically and radiographically for signs of musculoskeletal disorders. RESULTS: Workload to reach the desired fitness level was similar for CONDEX and PASTEX. CONDEX performed more prerace training sessions as 2-year-olds (P<0.05). The incidence of orthopaedic injuries was low in both groups and there were no differences in the occurrence of orthopaedic ailments. PASTEX animals tended to show signs of musculoskeletal disorders earlier than CONDEX animals. This time difference was significant for metacarpophalangeal joint pain on flexion, reduced carpal flexion and hindlimb lameness (P<0.05). CONCLUSIONS: Subjecting TB foals to conditioning exercise early in life does not have adverse effects on racing careers at ages 2 and 3 years, and does not influence the workload needed to reach a fitness level that is sufficient for racing. POTENTIAL RELEVANCE: The lack of negative effects and the indications of some positive effects of early conditioning exercise in the Thoroughbred encourage further large-scale comparative studies.     

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。     

伪狂犬病毒GDSH株的分离鉴定及gE基因的序列分析

从广东四会某猪场分离到一株疑为猪伪狂犬病病毒(PRV)的病毒,病毒在猪肾细胞上出现细胞变圆、拉网、融合等典型病变,并具有细胞泛嗜性特点。在MDCK细胞上测得其TCID50值为10-8/0.1mL,能被伪狂犬病病毒标准阳性血清中和。将0.1mL病毒液接种小鼠后发生奇痒并麻痹致死,接种猪3天后发病,7天死亡,从攻毒病死猪的脑组织病理切片上观察到典型的病毒性脑膜脑炎及血管套现象。通过PCR扩增到PRVgD基因,由此进一步证明所分离病毒为猪伪狂犬病毒,并命名为GDSH株。根据GenBank中发表的序列,设计一对扩增PRVgE基因的特异性引物,建立可以区分PRV野毒株与疫苗株的PCR诊断方法。以此方法对病毒的细胞培养液进行检测,结果证实所分毒株为PRV野毒株,经克隆测序后与GenBank收录的其它PRVgE基因序列进行比较,发现所测毒株的核苷酸序列与其它PRV毒株的同源性介于98.3%～99.9%之间,其中与PRVEa株的亲缘关系最近为99.9%。