Cell-free extract from porcine induced pluripotent stem cells can affect porcine somatic cell nuclear reprogramming

Pretreatment of somatic cells with undifferentiated cell extracts, such as embryonic stem cells and mammalian oocytes, is an attractive alternative method for reprogramming control. The properties of induced pluripotent stem cells (iPSCs) are similar to those of embryonic stem cells; however, no studies have reported somatic cell nuclear reprogramming using iPSC extracts. Therefore, this study aimed to evaluate the effects of porcine iPSC extracts treatment on porcine ear fibroblasts and early development of porcine cloned embryos produced from porcine ear skin fibroblasts pretreated with the porcine iPSC extracts. The Chariot^TM reagent system was used to deliver the iPSC extracts into cultured porcine ear skin fibroblasts. The iPSC extracts-treated cells (iPSC-treated cells) were cultured for 3 days and used for analyzing histone modification and somatic cell nuclear transfer. Compared to the results for nontreated cells, the trimethylation status of histone H3 lysine residue 9 (H3K9) in the iPSC-treated cells significantly decreased. The expression of Jmjd2b, the H3K9 trimethylation-specific demethylase gene, significantly increased in the iPSC-treated cells; conversely, the expression of the proapoptotic genes, Bax and p53, significantly decreased. When the iPSC-treated cells were transferred into enucleated porcine oocytes, no differences were observed in blastocyst development and total cell number in blastocysts compared with the results for control cells. However, H3K9 trimethylation of pronuclear-stage-cloned embryos significantly decreased in the iPSC-treated cells. Additionally, Bax and p53 gene expression in the blastocysts was significantly lower in iPSC-treated cells than in control cells. To our knowledge, this study is the first to show that an extracts of porcine iPSCs can affect histone modification and gene expression in porcine ear skin fibroblasts and cloned embryos.     

一起猪流行性腹泻病毒与博卡病毒混合感染病例分析

陕西渭南某猪场发生了一起仔猪腹泻病例,通过临床症状观察、病理解剖、细菌分离以及病原RT-PCR检测,确诊为一起流行性腹泻病毒混感博卡病毒病例。针对发病原因提出了防治措施,为防控仔猪腹泻提供参考。     

Porcine circovirus type 2 decreases the infection and replication of attenuated classical swine fever virus in porcine alveolar macrophages

Recently, it has been noted that porcine circovirus type 2 (PCV2) infection adversely affects the protective efficacy of Lapinized Philippines Coronel (LPC) vaccine, an attenuated strain of classical swine fever virus (CSFV), in pigs. In order to investigate the possible mechanisms of the PCV2-derived interference, an in vitro model was established to study the interaction of LPC virus (LPCV) and PCV2 in porcine alveolar macrophages (AMs). The results showed that PCV2 reduced the LPCV infection in AMs and the levels of PCV2-derived interference were dose-dependent. The PCV2-derived interference also reduced the replication level of LPCV in AMs. The full-length PCV2 DNA and its fragment DNA C9 CpG-ODN were involved in the reduction of LPCV infection in AMs, whereas UV-inactivated PCV2 was not. In addition, a moderate negative correlation between the LPCV antigen-containing rate and IFN-γ production was observed, and had a dose-dependent trend with the level of PCV2-inoculation. The results of the present study may partially explain how PCV2 infection interferes with the efficacy of LPC vaccine.     

Functional characteristics of porcine peripheral T cells stimulated with IL-2 or IL-2 and PMA

In human or mouse, mature T cells express either CD4 or CD8, resulting in different functions in the periphery. Interestingly, porcine CD4 and CD8 double positive (DP) T cells are present in the blood, and their proportions change from youth to adulthood. However, the features of these cells in swine are poorly understood. We investigated the fate of porcine peripheral T cells based on their functional characteristics, including proliferation and the expression of CD4 and CD8 co-receptors. The results showed that all the populations changed their CD8 expression in a time-dependent manner and porcine T cells had different proliferative pattern from human T cells. The results further revealed that Th2 cytokines were increased later in porcine T cells compared to human T cells upon stimulation with IL-2 + PMA. Collectively, we found that the fate of porcine peripheral T cells is different from that of human T cells, and the changes occur in a time- and stimulation-dependent manner.     

荧光定量PCR检测2型猪圆环病毒方法的建立

通过克隆2型猪圆环病毒（PCV2）的开放阅读框2（0RF2）基因编码其核衣壳蛋白（Cap）的一段靶序列,构建重组质粒作为标准阳性模板.根据GenBank中的靶序列设计一对引物和一条TaqMan探针.对PCR反应条件优化后,对构建的标准阳性模板定量,然后1 0＆#215;倍比稀释进行荧光定量PCR（qPCR）扩增并制作标准曲线,初步建立了PCV2检测的qPCR方法.结果表明,该方法检测灵敏度可达1.0＆#215;102拷贝/μ L,线性范围为101 ～ 109,达9个数量级,并且具有很好的特异性.对起始浓度为1.0＆#215;108、1.0＆#215; 106、1.0＆#215;104拷贝/μL的标准品的最终实际测得CT均值分别为12.77、19.72和26.89;变异系数分别为0.25％、0.10％和0.13％,均小于1％,说明此方法具有良好的准确性和重复性.     

对2014年春季上海市某猪场猪伪狂犬病暴发调查

2014年初,上海市闵行区某猪场妊娠母猪暴发妊娠障碍性疫病,疫病期间共发生34个流产病例,袭击率为11.8%。经现场流行病学暴发调查和实验室检测验证,判定该场暴发猪伪狂犬病疫情,建议立即实施猪伪狂犬病的紧急免疫、加强猪场内部管理并修改免疫程序,最终疫情得到有效控制。     

以 Balb／c 小鼠为动物模型的 PCV-2疫苗效力检验方法的建立

为建立以Balb／c小鼠为动物模型的 PCV-2疫苗免疫效力检验方法,选取4周龄 SPF级雌性Balb／c 小鼠20只,随机分成4组（Ⅰ、Ⅱ、Ⅲ、Ⅳ组）,每组5只,Ⅰ、Ⅱ和Ⅲ组分别背部皮下1点,背部皮下2点和背部皮下、腿部肌肉2点接种 PCV-2疫苗0．1、0．2、0．2 mL／只,Ⅳ组空白对照组不接种;各免疫组分别于首免疫后7、14、21 d 加强免疫一次,免疫后7、10、14、21、28、35、42 d 采血分离血清,用 ELISA 方法测定PCV-2特异性抗体,确定最佳免疫途径和免疫剂量。另选取4周龄 SPF 级雌性 Balb／c 小鼠,随机分成免疫组、攻毒对照组和健康对照组,免疫组和攻毒对照组于二免后14 d 用 PCV-2强毒株进行攻毒,比较各试验组小鼠在临床症状、病理变化、相对日增重、PCV-2核酸载量等方面差异性,确定小鼠动物模型检测指标。抗体测定表明,一免背部皮下、腿部肌肉2点免疫0．2 mL／只,间隔21 d 加强免疫为最佳免疫程序,免疫后35 d 抗体水平达到峰值,显著高于Ⅰ和Ⅱ组。对照组小鼠免疫攻毒后出现消瘦、被毛凌乱、精神紧张等临床症状,淋巴结肿胀、出血、肺脏出血等病理变化,相对日增重显著降低,PCV-2核酸载量差异在103以上等临床变化。本研究以 Balb／c 小鼠为动物模型建立了 PCV-2疫苗免疫效力检验方法,优化了小鼠免疫途径及剂量,确定了相应的检测指标及技术参数,为 PCV-2疫苗免疫效力检验奠定了基础。     

一起猪圆环病毒病并发猪瘟诊断分析

某市某猪场发生了一起以断奶后保育猪突然发病,发热,皮肤发红,贫血,下痢,衰竭为主要症状,发病率和死亡率很高的急性传染病,经流行病学调查、临床症状、剖检变化、实验室检查等综合诊断,确诊为猪圆环病毒病并发猪瘟混合感染,通过采取合理用药和防制措施,病情得到较好的控制。