季节性放牧对草地植物多样性与功能群特征的影响

针对放牧对高寒草地生态系统的影响,通过比较暖季放牧(6月-10月)和冷季放牧(11月-翌年5月)下典型高寒草地物种多样性和功能群特征的变化,分析了高寒草地植物群落对季节性放牧的响应机制。结果表明,暖季放牧草地中物种多样性指数为1.92,均匀度指数为0.78,明显高于冷季放牧草地的1.81和0.74,而冷季放牧草地的丰富度指数为17.45,高于暖季放牧草地的16.45。冷季放牧草地的地上生物量为246.61 g·m~(-2),莎草类和豆科类功能群的生物量比例分别为66.85%和15.86%,其值均高于暖季放牧草地。暖季放牧草地植物总密度为2 064株·m~(-2),明显高于冷季放牧草地的1 394株·m~(-2)。合理的放牧强度下,暖季放牧相比冷季放牧有利于草地群落物种多样性和均匀度的维持,但冷季放牧草地有利于草地群落地上生物量的积累。     

猕猴血清B病毒抗体3种检测方法的比较

为了解猕猴B病毒3种检测方法的检测效果,用3种方法对猕猴血清B病毒抗体分别进行检测并比较。结果表明,幼年组HSV-1EIA法检测结果与BV ELISA法比较差异显著(P<0.05),HSV-1EIA法与BV EIA法符合率96.6%,HSV-1EIA法与BV ELISA法符合率95.3%,BV EIA法与BVELISA法符合率98.7%。表明3种抗体检测方法检测结果符合率较高,均可以做为初筛检测,但BVELISA法在幼年猕猴血清B病毒抗体检测上敏感性最好。     

Orf virus circulation in cattle in Turkey

Orf virus (ORFV) causes contagious skin disease that mainly affects sheep and goats with zoonotic potential. However, there is not enough information about the association between ORFV and occurrence of skin disease in cattle. The present study describes outbreaks of ORFV infection in cattle in different provinces that are located in the Aegean, Central Anatolian and Mediterranean regions of Turkey. During the months of June and August 2017, vesicular fluid and scab samples were collected from cattle which had proliferative skin lesions. First, presence of lumpy skin disease virus (LSDV) and bovine herpesvirus 2 (BoHV-2, known as the causative agent of pseudo-lumpy skin disease) were investigated by real time PCR and PCR, respectively. Then, samples tested for the presence of parapoxviruses by PCR using primers specific to major envelope protein gene (B2L). Parapoxvirus DNA was detected in investigated samples whereas LSDV and BoHV-2 DNA were not detected. The analysis of the B2L gene sequences revealed that cattle were infected with ORFV. The isolates in the present study shared 100% sequence identity at the nucleotide and amino acid level when compared with previously characterised Turkish field ORFV isolates from goats in 2016. Results of the study show unusual infection of cattle with ORFV, and suggest that ORFV jumps the host species barrier from goats to cattle.     

猪流感病毒多表位融合蛋白对小鼠的免疫原性分析

作者拟利用表位多肽的抗原性及黏膜佐剂免疫增强作用,设计可通过黏膜途径免疫接种的猪流感病毒通用型疫苗.体外合成H1N1、H3N2亚型猪流感病毒表位抗原基因,C末端串联大肠杆菌热敏性肠毒素LTb基因,构建pET30(a)-ep-LTb表达载体,利用SDS-PAGE、Western blot分析重组融合蛋白表达及生物学特性,小鼠免疫试验分析融合蛋白免疫原性.SDS-PAGE检测表达蛋白相对分子质量约38 ku,主要以包涵体形式存在.重组蛋白可与抗His-tag抗体和CTB抗体发生特异性反应.ELISA及HI试验检测,经黏膜途径免疫的小鼠产生了针对重组表位模拟抗原蛋白及H1N1、H3N2亚型猪流感病毒的血清抗体及局部黏膜分泌型IgA抗体.利用猪流感病毒表位抗原与LTb基因串连获得的融合蛋白具有良好的免疫原性和反应原性,且在黏膜接种局部产生理想的分泌型IgA抗体,能有效阻断病原由黏膜局部感染,为研制猪流感病毒通用型疫苗奠定了基础.     

木聚糖酶产生菌的筛选鉴定及木聚糖酶基因(Xyn B)的克隆

采用富集培养、透明圈平板筛选的方法,从长期堆放青贮饲料的土壤中分离到7株木聚糖酶产生菌。选取透明圈最大的木聚糖酶产生菌X7作为基础菌,对其进行16S rRNA部分序列PCR扩增测定,经BLAST同源性分析确定X7为枯草芽孢杆菌Bacillus subtilis strain GD3b(Genebank编码:HM055602.1)。然后设计特异引物,以X7基因组为模板,对其进行Xyn B基因序列PCR扩增,扩增产物经BLAST同源性分析表明已成功克隆了X7菌株的Xyn B基因,为日后构建木聚糖酶基因酵母表达载体,培育能够分泌表达具有高活性的木聚糖酶酵母工程菌奠定了基础。     

化学修饰法制备B组轮状病毒生物素核酸探针及应用研究

用亚硫酸氢钠—乙二胺溶液对B组轮状病毒的ssRNA胞嘧啶修饰和转氨基作用，与生物素e—氨基己酸N—羟基琥珀酰亚胺酯反应，制备探针与样品在硝酸纤维膜上进行点杂交，经亲合素—碱性磷酸酶系统显色，可测出106.25－212.5pg的RNA靶序列，特异性试验表明：B组生物素探针只能与B组核酸杂交，而与无关核酸无杂交信号，用B组探针检测45份仔猪腹泻粪样，检出B组阳性5份，检出率11．1％，明显高于PAGE法，实验结果表明，生物素核酸探针制备简单并且有特异、灵敏、稳定的优点，可用于各组轮状病毒的检测。     

奶牛乳房炎与核转录因子κB基因的表达调控

核转录因子(nuclear factor-κB,NF-κB)是一个广泛存在于哺乳动物细胞中的转录因子,参与机体的免疫反应、细胞黏附、细胞分化、细胞增殖与凋亡及应激反应等。在奶牛感染乳房炎时,大部分涉及中性白细胞移行和激活的炎性蛋白质的编码基因在他们的启动子区都包含一个可结合NF-κB的κB位点,因此在一定程度上依赖NF-κB调控这些基因的表达。笔者详细的阐述NF-κB基因在奶牛乳房炎发病过程中的特点、作用和表达机制,为从分子水平认识和治疗奶牛乳房炎提供一定的文献支持。     

Brucellosis in Argentina

Brucellosis has been recognized in Argentina since the 19th century. Several studies demonstrated the presence of the disease in most of the domestic species. Actually, the estimate of prevalence is that between 10 and 13% of the farm animals are infected with bovine brucellosis with an individual rate of 4–5%. The annual economical losses have been estimated at US$ 60,000,000. The control of bovine brucellosis began in 1932 and successive resolutions have been issued since then. The current resolution indicates that B. abortus S19 is mandatory in female calves between 3 and 8 months of age. The vaccine strain B. abortus RB51 was provisionally approved but only for cattle older than 10 months of age. The brucellosis control program consists principally of test and slaughter. This methodology has been successful mainly in the dairy farms that have the incentive due to increased pricing because of obtaining a low prevalence of the disease. Brucellosis has been found in porcine, caprine, ovine and canine species. All Brucella species have been found in the country. Human brucellosis is an important disease and a national coordinated diagnostic net has been formed to better control the disease in man.     

江苏常州地区禽白血病血清学调查研究

为了解江苏常州地区肉鸡禽白血病病毒(ALV)感染情况,本研究采集了该地区2019年7-12月、2020年1-4月肉鸡血清样本1257份,通过ELISA试剂盒检测ALV-A/B、ALV-J、抗原p27阳性率。结果显示：在接受调查的两个地区均存在ALV感染及混合感染,且ALV-A/B感染率(13.13%)均高于ALV-J(5.01%);不同月份阳性率存在一定差异,ALV-A/B、ALV-J均为春夏季阳性率较高,秋冬季逐渐下降趋势;抗体阳性样本中有54.39%的p27抗原阳性率。本次调查为江苏常州地区商品肉鸡ALV净化及防控提供一定的参考依据。     

DNA甲基化酶抑制剂对体细胞染色体的影响

在动物的体细胞克隆过程中,供体细胞的细胞核要由高度甲基化状态转变为胚胎细胞的非甲基化状态,从而实现全能性的重新获得。试验利用DNA甲基化酶（5-aza-dc）抑制剂处理供体细胞,尝试建立一种既不影响染色体结构和数目,又能降低供体细胞细胞核的甲基化状态的最适浓度和方法,从而提供一种提高体细胞克隆动物效率的方法。在试验中,用不同浓度的甲基化酶抑制剂（5-aza-dc）处理奶牛成纤维细胞72 h,通过常规染色体核型分析方法制备染色体分裂相,检测其染色体数目、结构等的改变,结果显示,低浓度的甲基化酶抑制剂（0.005和0.01 μmol/L）处理,染色体没有发生明显的畸变（P＞0.05）,染色体能够保持正常的形态,高浓度（0.03与0.05 μmol/L）处理导致染色体畸变率显著增加（P＜0.05）,而0.1 μmol/L的5-aza-dc处理后染色体畸形率增加更为明显（P＜0.01）。总之,此试验的结果说明在对供体细胞做甲基化处理时用0.005和0.01 μmol/L的5-aza-dc处理不会影响细胞染色体结构和数目,但是高浓度处理则会导致染色体畸变率显著增加,不能用于体细胞克隆动物生产。