水牛cMyc基因与穿膜肽TAT的融合表达

为探讨干细胞转录因子与穿膜肽融合表达蛋白对水牛体细胞诱导重编程的可行性,作者对影响水牛cMyc基因穿膜肽融合蛋白表达的因素进行了探索。应用双酶切定向克隆的方法,将水牛cMyc基因CDS(1 350bp)连接到pET-HA2-TAT载体中,构建成pET-cMyc-TAT载体,经酶切、PCR和测序验证,载体构建正确。将pET-cMyc-TAT载体转化大肠杆菌BL21(DE3)感受态细胞,经IPTG诱导目的蛋白表达,同时探索了其表达形式、诱导表达IPTG最优浓度和最优时间以及蛋白纯化咪唑洗脱的最佳浓度。结果表明,融合蛋白cMyc-TAT在37℃以包涵体的形式大量表达,IPTG终浓度0.001mmol/L,诱导5h为最佳诱导条件,纯化蛋白最佳咪唑洗脱浓度为145.76mmol/L,纯化蛋白经过Western-blot验证具有抗原性。研究结果为建立转录因子穿膜肽融合蛋白诱导水牛iPS细胞技术体系奠定了基础。     

鸡马立克氏病病毒HC135分离株的致病性

从辽宁省某鸡场疑似马立克氏病发病鸡外周血淋巴细胞中分离到1株适应鸭胚成纤维细胞生长的马立克氏病病毒(MDV),经蚀斑克隆和细胞传代,成功培育了1株增殖性能稳定的MDV细胞毒株,命名为HC135株;将HC135株第4代细胞培养物分别人工感染非免疫和不同疫苗免疫的SPF鸡,分析其对鸡的致病力,分离毒株攻毒对照组鸡的发病率为100%(10/10),死亡率为30%(3/10);HVT疫苗及HVT/SB1双价疫苗对分离毒株的保护指数分别为22.2和40.0。结果表明,该毒株可以突破HVT疫苗和HVT/SB1双价疫苗的免疫保护,具有特超强毒株(vv+MDV)的特点;也证实了我国商品鸡群中存在vv+MDV毒株。同时比较了HC135株与14株参考毒株的Meq基因序列,发现其Meq基因的ORF内没有基因片段的插入或缺失,推导的氨基酸存在点突变,这种突变符合高毒力毒株的变异规律。     

鲫鱼ghrelin基因的克隆和生物信息学分析

从鲫鱼的肠道内提取总RNA,运用RT-PCR扩增ghrelin基因并测序,用生物信息学软件预测其结构,并构建系统进化树,探讨了鲫鱼ghrelin基因的生物学功能,为进一步研究该基因对鲫鱼摄食的影响奠定基础。结果显示,获得了长490bp的ghrelin基因(GenBank登录号为HM567312),其序列含有1个312bp的完整开放阅读框,编码103个氨基酸;ghrelin蛋白分子质量为11 519.48u,等电点为5.20,半衰期为1.20h,不稳定系数为31.29,总平均亲水性为0.727,疏水性为-2.900～2.856;1～26位氨基酸可能是信号肽序列;在ghrelin的分子序列中存在44处α螺旋富集区域,8处β折叠区域,集中于成熟肽部分,有43处无规则卷曲。系统进化树分析显示鲫鱼ghrelin基因与金鱼的进化距离最近。     

Gene expression during blow fly development: improving the precision of age estimates in forensic entomology

Forensic entomologists use size and developmental stage to estimate blow fly age, and from those, a postmortem interval. Since such estimates are generally accurate but often lack precision, particularly in the older developmental stages, alternative aging methods would be advantageous. Presented here is a means of incorporating developmentally regulated gene expression levels into traditional stage and size data, with a goal of more precisely estimating developmental age of immature Lucilia sericata. Generalized additive models of development showed improved statistical support compared to models that did not include gene expression data, resulting in an increase in estimate precision, especially for postfeeding third instars and pupae. The models were then used to make blind estimates of development for 86 immature L. sericata raised on rat carcasses. Overall, inclusion of gene expression data resulted in increased precision in aging blow flies.     

小鼠皮肤损伤后时序芯片数据分析及关键基因的筛选

目的 应用生物信息学方法对皮肤损伤后不同时间点的差异表达基因(differentially expressed genes,DEGs)进行分析,为法医学皮肤损伤时间推断(wound age estimation)提供理论依据.方法 从基因表达综合数据库(gene expression omnibus,GEO)下载基因芯...     

猪IL-18基因的原核表达及重组蛋白的纯化

以pcDNA3.1-pIL-18为模板,采用PCR技术扩增到了猪白细胞介素18(IL-18)的成熟蛋白基因,通过KpnⅠ SacⅠ双酶切及连接反应,构建了pET32c-pIL-18原核表达质粒。经过限制性内切酶分析、PCR鉴定及DNA序列测定证实,重组质粒中的基因片段连接正确。之后,重组质粒转化大肠杆菌BL21(DE3),于37℃、1.0 mmol/L IPTG条件下诱导表达。菌体裂解产物经SDS-PAGE分析,在分子质量约为33 ku处出现了预期的目的蛋白。用8 mol/L脲对表达产物变性,经Ni2 -NTA柱纯化,透析复性,得到了纯化的IL-18蛋白。Western-blot分析证实,纯化的重组IL-18蛋白具有反应活性。上述研究结果为重组IL-18的应用奠定了基础。     

天祝白牦牛MSTN基因第3外显子的多态性分析

为分析天祝白牦牛MSTN基因第3外显子的遗传多态性及变异特征,采用PCR-SSCP方法检测了698头天祝白牦牛MSTN基因第3外显子的多态性,对群体内各等位基因进行了克隆、测序。结果显示,天祝白牦牛MSTN基因第3外显子有AA、AB和BB 3种基因型,其基因型频率分别为0.892 6、0.106 0和0.001 4,由A和B 2个等位基因控制。序列分析表明,天祝白牦牛MSTN基因第3外显子在41bp处发生了A→G突变,但并未导致编码氨基酸序列发生改变。统计结果表明,天祝白牦牛MSTN基因第3外显子呈低度多态。     

基于RhoA/ROCK通路研究天麻素对高血压病左心室肥厚大鼠心室重构的影响

目的 观察天麻素对高血压病左心室肥厚大鼠心室重构的影响,从Ras同族体基因家族成员A(Ras homolog gene family member A,RhoA)/Rho激酶(Rho-associated kinase,ROCK)通路探究其作用机制.方法 将100只SD雄性大鼠随机分为假手术组,模型组,天麻素低剂量(1...     

Prescribing engagement in environmental risk assessment for gene drive technology

Gene drive technology is a nascent biotechnology with the potential to purposefully alter or eliminate a species. There have been broad calls for engagement to inform gene drive governance. Over the past seven years, the gene drive community has been developing risk assessment guidelines to determine what form future gene drive risk assessments take, including whether and how they involve engagement. To explore who is developing these guidelines and how engagement in risk assessment is being prescribed, we conduct a document analysis of gene drive risk assessment guideline documents from 2014 to 2020. We found that a narrow set of organizations have developed 10 key guideline documents and that with only one exception the documents prescribe a narrow, vague, or completely absent role for engagement in gene drive risk assessment. Without substantively prescribed engagement in guidelines, the relevance, rigor, and trustworthiness of gene drive risk assessment and governance will suffer.