LncRNA在动物科学中的研究进展

长链非编码RNA(long non-coding RNA,LncRNA)是一类长度大于200 nt的非编码RNA,能够存在于细胞核和细胞质中.LncRNA能够以顺式和反式作用方式调节基因表达,是一类重要的基因表达调节分子.LncRNA参与细胞分化发育、X染色体失活、肿瘤、免疫、神经系统和心血管系统疾病等多种生物过程和疾病的调控,具有重要的研究价值.作者主要对LncRNA的分类和来源、作用机制、研究现状及其在畜牧兽医中的研究情况进行了综述,为LncRNA在兽医和畜牧业科学中的研究和应用提供参考.     

Effect of weaning time on the performance of Trachinotus ovatus (Linnaeus 1758) larvae

Effect of weaning time on the larval performance of golden pompano Trachinotus ovatus was studied in the experimental condition. The same weaning regime started on four different days of posthatch (DPH): 13 DPH (W13), 16 DPH (W16), 19 DPH (W19) and 22 DPH (W22), respectively. Growth, survival, RNA/DNA ratios and mid‐gut cell height of fish were assessed in each weaning regime over time. Growth and survival rates of fish larvae weaned in the W19 and W22 regimes were significantly higher than those in the W13 and W16 regimes. No significant differences were found either between W19 and W22, or between W13 and W16 treatments. Fish showed a decrease in the RNA/DNA ratio in W13, but a trend of increase in W16, W19 and W22. Weaning time significantly affected the mid‐gut cell height in larval golden pompano. On 24 DPH, the mid‐gut cell height of fish in the W13 and W16 treatments was significantly thinner than those in the W19 and W22 treatments. Based on fish growth, survival, RNA/DNA ratio and mid‐gut cell height, weaning can be started on 13 DPH in golden pompano larvae, but we recommend that the best weaning window be 16–22 DPH. These results are supported by histological and nutritional evidence and would guide the weaning process for golden pompano larvae, and offer a useful approach to explore the weaning protocol in larval fish rearing.     

Effects of dietary microbial levan on growth performance,RNA/DNA ratio and some physio‐biochemical responses of Labeo rohita (Hamilton) juveniles

Six isonitrogenous and isocaloric semi‐purified diets were prepared with different levels of microbial levan: control (Basal), T1 (Basal + 2.5 g kg^?1 diet), T2 (Basal + 5 g kg^?1 diet), T3 (Basal + 7.5 g kg^?1 diet), T4 (Basal + 10 g kg^?1 diet) and T5 (Basal + 12.5 g kg^?1 diet), fed to six groups of fish in triplicate tanks. The results of the 60 days feeding trail showed that supplementation of dietary levan significantly affected the weight gain percentage and specific growth rate of the treatment groups fed at 10 g kg^?1 or more levan. Lowest feed conversion ratio (FCR) value and highest survival percentage among levan fed groups were observed with 12.5 g kg^?1 incorporation (T5) and was comparable with (T4) group. Significant increase in muscle RNA level and RNA/DNA ratio was observed with the increasing dietary levan. Fish fed 12.5 g kg^?1 levan had significantly higher protease, amylase and lipase activities compare with the control group. Lowest Aspartate aminotransferase (AST) activity in the liver and muscle was observed in the T5 group fed with highest level of dietary levan. Overall results conclude that dietary microbial levan incorporation at 12.5 g kg^?1 could be used as potent dietary prebiotic for the culture of L. rohita juveniles.     

利用siRNA高通量测序技术检测烟草病毒

<正>烟草是我国的主要经济作物之一,病毒病是烟草生产上的重要病害。常见的烟草病毒主要有马铃薯Y病毒(Potato virus Y,PVY)、黄瓜花叶病毒(Cucumber mosaic virus,CMV)、烟草花叶病毒(Tobacco mosaic virus,TMV)、烟草脉带花叶病毒(Tobacco vein banding mosaic virus,TVMBV)等[1]。此外,近年来在烟草上还发生一些新的病毒病害,如南美红辣椒脉斑驳病毒(Chilli veinal mottle virus,ChiVMV)[2]、番茄环纹斑点病毒(Tomato zonate spot virus,ZTSV)[3]和番茄斑萎病毒(Tomato spotted wilt virus,TSWV)[4]。这些病毒     

山西短颈剑线虫(Xiphinema brevicollum)形态与rDNA分子特征

采用浅盘分离法在山西太谷松树根际土壤中分离得到一种剑线虫,通过Seinhorst脱水制片后利用显微镜观察其形态特征并进行测量,其主要特征为:雌性虫体经热杀死后呈腹面弯曲的"C"形,体长1.71~2.26mm,两端渐细;齿针全长127.3~140.8μm;a(体长/体宽)为35.9~51.4μm,b(体长/食道外宽)为5.8~8.7μm,c(体长/尾长)为50.7~103μm。前卵巢与后卵巢长短相近,尾形近似圆锥形。未见雄虫。对该线虫的rDNA-ITS1,rDNAITS2和28SRNA序列进行扩增、测序及系统进化分析,结合形态学特征进行鉴定,将分离到的剑线虫鉴定为短颈剑线虫(Xiphinema brevicollum),这是山西首次发现报道剑线虫属的一个种。     

青虾transformer-2基因RNA干扰规律的研究

通过对青虾性别调控相关基因transformer-2（tra-2）的RNA干扰规律进行研究,探讨了tra-2 基因RNA干扰的最适注射部位、注射剂量、干扰效果以及干扰规律等。通过对青虾肌肉、心脏、围心腔和眼柄基部注射比较发现,围心腔注射死亡率最低,适宜RNA干扰研究。采用4 μg/g 的dsRNA剂量进行时间依赖性干扰试验,RT-PCR检验注射后第1,7,14 天的卵巢tra-2 表达量,结果显示第7 天基因表达量出现显著降低（P<0.05）。不同剂量水平（0.4 μg/g、4 μg/g 以及12 μg/g）干扰研究发现,0.4 μg/g dsRNA没有干扰结果,4 μg/g 和12 μg/g 剂量的干扰效果均显著。与4 μg/g 的剂量相比,12 μg/g 的dsRNA能在较短时间内起到明显的干扰效果,且能持续较长的时间,表明干扰规律会随着剂量的改变而变化。但两组tra-2的最低表达量分别为正常水平的23%和21%,无显著差异（P>0.05）。     

甘蔗黄叶病毒P0蛋白分子特性及其抑制RNA沉默活性

【目的】甘蔗黄叶病（yellow leaf,YL）是一种主要的甘蔗病毒病害,在全球多数甘蔗种植国家或地区普遍发生,已对甘蔗生产造成严重威胁。其病原为甘蔗黄叶病毒（Sugarcane yellow leaf virus,SCYLV）,属于黄症病毒科马铃薯卷叶病毒属成员。研究SCYLV编码的沉默抑制子P0蛋白的分子特征、保守结构域及其在自然寄主甘蔗上抑制RNA沉默的功能,为下一步从RNA沉默水平解析SCYLV致病分子机理奠定基础。【方法】利用RT-PCR克隆技术获得SCYLV中国分离物CHN-FJ4编码的RNA沉默抑制子基因P0及其两个缺失突变体P0^Δ2-15（N端缺失15个氨基酸）和P0^Δ155-256（C端缺失102个氨基酸）,然后定向克隆到单子叶植物表达载体pUbi-nos（空载体）上,获得重组质粒。利用甘蔗嫩叶组织瞬时表达系统鉴定病毒RNA沉默抑制子技术,结合ImageJ软件定量分析P0及其两个缺失突变体抑制外源基因EYFP瞬时表达活性的变化。番茄丛矮病毒（Tomato bushy stunt virus,TBSV）编码的P19作为沉默抑制子阳性对照。【结果】P0核苷酸序列的遗传进化分析结果显示,所获得的SCYLV病毒分离物CHN-FJ4为BRA基因型,与其他BRA基因型分离物氨基酸序列一致性为96.1%-98.4%。利用MEME在线软件预测P0蛋白的保守结构域,结果表明P0蛋白含有3个显著的保守区。分别位于第1-60、76-125和161-210氨基酸残基。通过Datamonkey在线服务器（http://www.datamonkey.org）提供的5种运算方法分析P0蛋白氨基酸位点的选择压力,结果显示P0蛋白具有8个氨基酸正向选择位点。将含有P0及其缺失突变体的重组质粒连同含EYFP报告基因的pTEM12质粒采用基因枪轰击法分别导入甘蔗嫩叶组织细胞,轰击后48-120 h,P0和P19逐渐地提高EYFP荧光表达点数和荧光表达水平;在120 h,与pUbi-nos空载体（不含沉默抑制子）对照组相比,P0和P19均显著地提高甘蔗嫩叶组织EYFP荧光表达点数和荧光表达水平,分别达1.6倍和4.0倍以上。P0与P19抑制RNA沉默活性水平没有显著差异（P>0.05）。P0蛋白N端缺失15个氨基酸（P0^Δ2-15）和C端缺失102个氨基酸（P0^Δ155-256）均丧失了沉默抑制子的功能,荧光表达与不含沉默抑制子对照组相当。【结论】在甘蔗嫩叶组织EYFP瞬时表达体系上,P0能够显著地提高外源基因EYFP表达水平。P0蛋白N端15个氨基酸和C端102个氨基酸含有显著的保守区域,是P0发挥沉默抑制子功能所必需的。