3株鸽源新城疫病毒的分子特征及对鸽的致病性

2011―2013年在新城疫流行病学调查中分离到3株鸽源新城疫病毒(SDS,SD01和SD02),为了进一步了解其生物学特性和遗传进化规律,对3株病毒进行了测序和生物活性分析,并对分离株SDS对鸽的致病性进行了评价。结果表明,毒株SDS基因组全长为15192 bp,基因排列方式为3′-NP-P-M-F-HN-L-5′,3个分离株F蛋白裂解位点氨基酸序列均为¹¹²RRQKRF¹¹⁷,具有典型的新城疫强毒的分子特征。系统进化分析表明这3个毒株与基因Ⅵ型NDV毒株聚于一簇,属于ClassⅡ系Ⅵb基因型。3个分离株F蛋白的融合肽和七肽重复区,HN蛋白的抗原中和表位存在多处突变,与单克隆抗体1E5、2F10的反应性也发生改变,表明3个分离株与疫苗株LaSota有明显的抗原差异。SDS攻毒试验结果显示,试验鸽自攻毒后5 d出现明显的临床症状,滴鼻组和肌肉注射组的死亡率分别为60%和70%;病死鸽剖检可见脑膜充血出血,腺胃乳头、腺胃肌胃交界及肠道出血,肝脏肿大,脾有淤血斑。滴鼻组在攻毒后5~14 d于喉头和泄殖腔检出排毒,而肌肉注射组在攻毒后3~14 d于喉头和泄殖腔有排毒。     

CRISPR/Cas9介导的多基因编辑系统在大豆中的应用

自CRISPR/Cas9（clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9）基因 组编辑技术发现以来，迅速在作物中得到广泛应用。但是，CRISPR/Cas9多基因编辑系统在大豆中的研究尚待开 发。本文利用CRISPR/Cas9介导的多基因编辑系统，分别构建了两个载体，一个载体含6个靶点，编辑7个大豆基因 （4个Glycine max ASYMMETRIC LEAVES1（GmAS1）同源基因和3个GmAS2 同源基因），另一个载体含8个靶点，编辑 11个G. max AGAMOUS 家族同源基因（4个GmAG 同源基因，2个G. max SEEDSTICK（GmSTK）同源基因和5个G. max SHATTERPROOF1（GmSHP1/2）同源基因）。大豆遗传转化后，经表型鉴定和靶点检测发现，CRISPR/Cas9介导的多 基因编辑系统在大豆中成功实现了多基因编辑。当3个GmAS1 同源基因和3个GmAS2 同源基因同时突变时，导致 大豆叶片向远轴面弯曲、皱缩且叶柄变短的表型。当2个GmSHP1 同源基因和2个GmSTK 同源基因同时突变时，导 致豆荚停止发育的不育表型。     

绿色富硒生物猪饲料中AFB1达标生产工艺优化研究

饲料中黄曲霉毒素(AFB₁)容易超标,检出率达80%~100%,毒性大,具强致癌性,可抑制生猪免疫机能,降低动物生产性能,引起动物继发感染,还会在动物产品中残留而威胁人类健康,给生猪养殖带来经济损失,降低猪肉食品安全性。本文通过使用先进固体发酵系统设备和益生菌发酵技术,采用单因素试验和响应面中试优化,获得发酵降解猪饲料AFB₁的最佳工艺参数为硒浓度0.3 mg/kg,发酵时间12 h,量子波强度30 Hz,益生菌菌种组合CGMCC NO.17328混合CGMCC NO.15611。该工艺将猪饲料AFB₁量从63.41μg/kg降解到2.98μg/kg,降解率达到95.30%,AFB₁含量达到国家饲料安全标准。生产工艺适合养猪场低成本快速生产AFB₁达标猪饲料。     

The integration and insertion site of GbVe1 gene in the genome of transgenic cotton (Gossypium hirsutum)

[Objective] The aim of this study was to obtain the flanking sequences of T-DNA in the transgenic cotton containing a GbVe1 over-expression cassette. [Method] The T-DNA insertion copy number in the transgenic GbVe1 cotton was analyzed by southern blot. Flanking sequences of the transgenic lines with putative single T-DNA insertion copy were obtained using high-efficiency Thermal asymmetric interlaced polymerase chain reaction (hiTAIL-PCR). The T-DNA insertion sites were further confirmed by PCR with specific primers. [Result] RB-flanking sequences (119-1 018 bp) and LB-flanking sequences (243-516 bp) were obtained from three transgenic lines with low copy number of T-DNA insertion. The AT content was more than 63% in these flanking sequences. A same single insertion site in the intron of Gohir.D01G157600.1 was found in the two transgenic lines 7/100826-152 and 12/100826-393, while two separated insertion sites, one also in the intron of Gohir.-D01G157600.1 and the other in the intergenic region of A12 chromosome, were found in the transgenic line 1/w-ch14. A deletion of 21 bp was found in the insertion site in the intron of Gohir.D01G157600.1. The T-DNA insertion in the intron of Gohir.D01G157600.1 was further confirmed by the specific PCR. [Conclusion] The flanking sequences of T-DNA in the transgenic GbVe1 cotton were obtained and the specific transformation event in the intron of Gohir.D01G157600.1 was further confirmed by PCR.     

Production,Characterization and Immunomodulatory Activity of an Extracellular Polysaccharide from Rhodotorula mucilaginosa YL-1 Isolated from Sea Salt Field

A novel exopolysaccharide from marine-derived red yeast Rhodotorula mucilaginosa strain YL-1 was produced and characterized. The highest yield of polysaccharide reached 15.1 g/L after medium and culture parameter optimization. This exopolysaccharide, composed of four neural monosaccharides including glucose, mannose, galactose and fucose, had an average molecular weight of 1200 KDa. It had good immunomodulatory activity on RAW256.7 cell lines. ELISA (enzyme linked immunosorbent assay) and Q-PCR (quantitative real-time PCR) results showed that the cell was stimulated to express more IL-6, IL-18, IL-1β and TNFα cytokines than the control group. This is the first report of an exopolysaccharide with immunomodulatory activity from marine-derived Rhodotorula mucilaginosa.     

谷氨酰胺对斜带石斑鱼GF-1细胞中C-Myc蛋白的表达与神经坏死病毒复制的影响

为探讨C-Myc表达、谷氨酰胺代谢和神经坏死病毒复制三者之间的关系,本研究首先克隆了斜带石斑鱼鳍条细胞(GF-1)中的C-Myc基因(GF-1-C-Myc),结果显示GF-1-CMyc基因cDNA全长814 bp,开放阅读框(ORF)为285 bp,编码95个氨基酸(aa),有亮氨酸拉链结构域与螺旋-环-螺旋(HLH)结构域。实验表达和纯化了GF-1-C-Myc蛋白,并制备其多克隆抗体。采用实时定量PCR技术(qRT-PCR)与免疫印迹法(WB)检测了GF-1-C-Myc基因的表达和神经坏死病毒的复制。结果显示,缺乏谷氨酰胺会同时抑制GF-1-C-Myc基因的表达和神经坏死病毒(NNV)的复制,添加谷氨酰胺可同时促进GF-1-C-Myc的表达和NNV的复制;此外,NNV感染可上调GF-1-C-Myc基因的表达,并显著消耗GF-1细胞培养液中的谷氨酰胺。研究表明,GF-1-C-Myc基因可调控宿主谷氨酰胺代谢,从而有利于神经坏死病毒的复制。本结果为防控NNV的感染提供了参考。     

湖南省粮食产量波动的影响因素分析及预测

旨在维护国家稳定,为预判粮食生产前景、提高粮食生产效率、保障粮食安全提供理论依据。利用湖南省统计数据,运用灰色关联分析法筛选关联性较强的影响因素,并建立GM(1,N)预测模型预测粮食产量。2008—2017年与湖南省粮食产量关联度最大的影响因素是粮食作物播种面积和农业机械总动力;科技因素是影响2008—2017年湖南省粮食产量的主要因素,其次是自然因素,社会因素;2018—2027年湖南省粮食产量有较小波动,且农业机械总动力和财政农业支出影响较大;农业机械总动力在前后十年对粮食产量都有较重要的影响,越来越占据主导地位。粮食产量受国家政策的影响,受农业机械总动力影响最大,维持产量水平需高度重视农业机械化水平,稳步提高粮食作物播种面积。