鸡Ii结合Rab5a和Rab7b分子的分析

本研究旨在探明鸡恒定链（invariant chain，Ii）与内吞体转运蛋白Rab5a和Rab7b结合的结构域和在细胞内共定位的特征。首先，用PCR和基因突变技术将Ii胞浆区与跨膜区[Ii_{（Cyt-Tra）}]、Ii CLIP （class Ⅱ-associated invariant chain peptide）-三聚体区[Ii_{（CLIP-TRIM）}]和Ii突变体[Ii_{（M81-87aa）}、Ii_{（M91-99aa）}和Ii_{（M81-99aa）}]分别插入pET-32a和pEGFP-C1构建相应的原核和真核重组质粒。其次，将构建的含有绿色荧光蛋白的重组质粒与实验室保存的含有红色荧光Rab5a和Rab7b的重组质粒共转染至人胚胎肾细胞系293 T，观察它们的共定位。将构建的原核重组质粒进行表达和纯化，最后用拉下法和免疫印迹检测Ii与Rab5a和Rab7b的结合域。结果表明，成功构建Ii结构域及Ii突变体的重组质粒。Ii_{（Cyt-Tra）}及Ii突变体均能与Rab5a和Rab7b在细胞内共定位，而Ii_{（CLIP-TRIM）}与空载体却不能。Ii的胞浆区和跨膜区是与Rab5a和Rab7b结合的功能结构域，而不是CLIP与三聚体区。综上所述，鸡Ii与Rab5a和Rab7b共定位和结合的区域是其胞浆区和跨膜区，而不是内质网腔区。这些结果提示Rab分子参与了Ii在胞内细胞器的转运机制，为进一步研究Ii及其载体在细胞内的转运机制和功能提供了新的途径。     

滴灌下生物质改良材料对盐渍土水盐氮运移的调控效应

为探究生物质改良材料对滴灌盐渍土水、盐、肥运移过程的调控效应，采用土箱模拟试验，研究了水肥一体化滴灌条件下，生物炭和腐殖酸两种改良材料对盐渍土水、盐、氮运移和再分布过程及其时空分布特征的影响规律。结果表明：在滴灌条件下，盐渍土壤水盐的时空动态变化表现出明显的水分入渗驱动的盐分运移过程和蒸发扩散驱动的水盐再分布过程；铵态氮含量在时间上表现出先增大、后减小的变化趋势，在空间上的运移再分布特征较弱；硝态氮含量初始时空分布表现出与水盐相似的运移特征，受铵态氮硝化作用的多重影响，后期空间分布与铵态氮空间分布相似；生物炭通过提高土壤饱和导水率，增大了入渗阶段土壤水、盐、氮的运移速率和分布范围；腐殖酸通过提高土壤田间持水率增大了再分布过程土壤水、盐、氮的分布范围和强度，同时其对尿素的水解和硝化过程表现出更强的抑制效果。应用生物质改良材料在改变土壤物理性状进而调控滴灌土壤水盐运移的同时，还影响土壤氮素转化运移过程及其分布，这为水肥一体化滴灌盐渍农田的节水、控盐、减肥治理提供了理论基础。     

青海省祁连圆柏天然林单木生物量模型构建

利用祁连圆柏整株生物量与生长指标数据，为估算祁连圆柏林的生物量估算提供参考。通过野外调查，共获取了63株祁连圆柏天然林样木生物量与生长指标实测数据。用其中50株样木数据进行回归模拟，用其余的13株样木数据对模型可靠性进行检验，构建器官生物量与生长指标间的回归模型。结果表明，祁连圆柏单木水平下，树干生物量模型的R²_adj为0.96，均方根、模型有效性和残差系数分别为0.50、0.85和0.05；枝条生物量模型的R²_adj为0.897，均方根、模型有效性和残差系数分别为0.69、0.80和-0.66；叶生物量模型的R²_adj为0.61，均方根、模型有效性和残差系数分别为0.54、0.86和0.15；根生物量模型的R²_adj为0.93，均方根、模型有效性和残差系数分别为0.12、0.997 和-0.01。在调查数据范围内构建的模型较好地反映了祁连圆柏生物量与生长指标间的关系，形式简单、使用方便；与实测值相比，树干与叶生物量模拟值偏小，枝和根偏大。     

南海大顶苦瓜规范化栽培技术

为了发挥广东省佛山市的传统特色蔬菜——大顶苦瓜的产品优势,提高农户的规范化栽培技术水平,在改良南海大顶苦瓜品种的基础上,制定出配套的规范化栽培技术措施,内容包括品种特性、产地环境要求、育苗、田间管理措施和采收,旨在进一步提高南海大顶苦瓜的生产效益,大力推广这一传统特色蔬菜品种。     

Comparison of the microbial communities of alpacas and sheep fed diets with three different ratios of corn stalk to concentrate

The objective of this study was to investigate the characteristics of ruminal microbial communities of alpacas (Lama pacos) and sheep (Ovis aries) fed three diets with varying ratios of roughage (corn stalk) to concentrate, 3:7 (LS), 5:5 (MS) and 7:3 (HS). Six alpacas (one-year-old and weighing 29.5 ± 7.1 kg) and six sheep (one-year-old and weighing 27.9 ± 2.7 kg) were used in this study, in a replicated 3 × 3 Latin square experiment. Total protozoa concentration was determined under the microscope; total fungi and methanogens were assessed using quantitative polymerase chain reaction and expressed as a percentage of total bacterial 16S rRNA gene copies; bacterial communities were investigated by targeted 16S rRNA gene (V3–V4 region) sequencing. The percentage of fungi was significantly higher in alpacas than in sheep under the LS diet, while the concentration of protozoa was significantly lower in alpacas under HS, MS and LS diets. The alpha diversity including Shannon, Chao l and ACE indices of bacterial communities was higher in alpacas than in sheep, under the LS diet. A total of 299 genera belonging to 22 phyla were observed in the forestomach of alpaca and sheep, with Bacteroidetes and Firmicutes dominating both animal species. Phyla Armatimonadetes and Fusobacteria, as well as 64 genera, were detected only in alpacas, whereas phyla Acidobacteria and Nitrospira, as well as 44 genera, were found only in sheep. The abundance of cellulolytic bacteria, including Butyrivibrio and Pseudobutyrivibrio, was higher in alpacas than in sheep under all three diets. These differences in the forestomach microbial communities partly explained why alpacas displayed a higher poor-quality roughage digestibility, and a lower methane production. Results also revealed that the adverse effects of high-concentrate diets (70%) were lesser in alpacas than in sheep.     

Screening and Verification of Low Nitrogen Tolerant and Nitrogen Sensitive Cotton Germplasm

[Objective] The aim of this study is to evaluate nitrogen efficient cotton germplasms and improve nitrogen use efficiency. [Method] Eighty cotton germplasms were selected and evaluated in the hydroponic experiment under low (0.25 mmol·L^－1) and high (5 mmol·L^－1) nitrogen concentration. Different traits for screening were identified and nitrogen use efficiency types were classified. Field experiments were also performed for comparison and confirmation of the identified germplasms. [Result] The results showed that there were significant differences in the total plant dry matter, shoot nitrogen accumulation and nitrogen absorption efficiency in cotton germplasms at the two nitrogen levels. Based on coefficient of variation, principal component analysis and correlation, six traits including total plant dry matter, shoot dry matter, root dry matter, total nitrogen accumulation, shoot nitrogen accumulation and nitrogen absorption efficiency were used as screening indicators. According to the Heatmap clustering analysis and the nitrogen efficiency comprehensive index, two germplasms (Lu05R59 and CCRI 69) were identified as low nitrogen tolerant and nitrogen efficient, and two germplasms (Coker 201 and Xinluzhong 30) as low nitrogen sensitive and nitrogen inefficient. The results of field experiment were consistent with the results of the hydroponic culture at the seedling stage. [Conclusion] It was finally determined that Lu05R59 and CCRI 69 were the low nitrogen tolerant and nitrogen efficient germplasms, and Coker 201 and Xinluzhong 30 were low nitrogen sensitive and nitrogen inefficient germplasms. The results of these studies provide the possibility for screening and rapid identification of nitrogen use efficiency in cotton at the seedling stage, and provide the ideal materials and theoretical basis for further study of cotton nitrogen efficient.     

芸薹属及其他异源多倍体植物的基因表达特征研究进展

远缘杂交及异源多倍化导致许多重要作物的起源与进化，而芸薹属栽培异源四倍种是研究作物异源多倍化的模式系统之一。异源多倍体是如何调控及协调来自不同二倍体祖先的不同基因组的遗传行为及基因表达，是过去二十年间的研究热点和重要的生物学问题。利用不断发展的分子生物学技术，一方面揭示出芸薹属及其他多倍体物种基因组表现出动态性质，即在形成初期及长期进化过程中持续发生遗传及表观遗传的变化；另一方面发现异源多倍化过程中伴随着大量的基因表达模式改变，包括非加性表达、超亲表达、表达水平显性、部分同源偏向表达、基因剂量平衡效应等现象。上述基因组结构、表观遗传改变以及基因表达模式的调控，使新产生的多倍体得以成功进化为新物种。     

Identification of an H1N1 subtype of swine influenza virus and serological analysis

To investigate the epizootic of swine influenza virus(SIV), 60 nasal swabs were collected from a clinical cases of pig farm in Tai'an City, Shandong Province of China in April 2017. SIV was isolated by inoculating into 10-day-old Special Pathogen Free embryonated eggs and the whole genome was sequenced. An H1N1 subtype SIV was isolated and designated as A/swine/Shandong/TA04/2017(H1N1). Phylogenetic analysis showed that apart from the polymerase A(PA) fragment belonging to the 2009 pandemic H1N1 branch, seven genome segments belonged to avian-like H1N1 influenza virus lineage. The cleavage site sequence of the hemagglutinin(HA) protein was PSIQSR↓G, which is a typical molecular biological characteristic. Five potential N-glycosylation sites(N14, N26, N277, N484 and N543) were found in the HA gene. To further investigate the epidemiology of SIV in this farm, the 995 serum samples were assessed with EAH1N1 2009 pandemic H1N1 and H3 N2 antigens. The results showed that the total positive rate was 65.43%. The positive rates of single virus infection detected by EAH1N1, 2009 pdmH1N1 and H3 N2 for serum HI(Hemagglutination inhibition) were 48.35, 30.85 and 7.47%, respectively. The results showed that SIV in Shandong Province has been reassorted in some segments and the SIV-positive rate was high on the SIV outbreak farm. These data provide evidence of an epizootic of SIV.     

异硫氰酸丙烯酯毒杀松材线虫作用机制初步研究

对异硫氰酸丙烯酯毒杀松材线虫作用机制进行了初步研究。测定了其对线虫虫体形态、运动行为、体内总糖和蛋白质含量的影响,以及处理前后线虫体内过氧化氢酶(CAT)、乙酰胆碱酯酶(AChE)和谷胱甘肽-S-转移酶(GST)活性变化。结果表明:经异硫氰酸丙烯酯处理后的松材线虫虫体形态严重扭曲,运动形态出现由正常的S形变化为多节弯曲和螺旋状卷曲等异常状况,线虫行动随时间的推移变得迟缓,最终呈C形、新月形或直接死亡。随着异硫氰酸丙烯酯处理质量浓度的增大,线虫体内总糖和蛋白质含量显著上升,糖和蛋白质的代谢发生紊乱;线虫体内CAT、AChE和GST活性显著降低,且均低于对照组,表明线虫体内氧化和抗氧化作用失衡;细胞受到极大的影响,神经系统遭到破坏,解毒能力明显降低。研究结果可为研究利用异硫氰酸丙烯酯作为植物源杀线虫剂提供依据。