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.     

粪肠球菌生长曲线的测定及其对小鼠脑组织的影响

为测定致羔羊脑炎粪肠球菌（Enterococcus faecalis）的生长曲线，寻求一种快速而准确的方法测定不同生长时期粪肠球菌数量，并客观评价其毒性强弱及其对小鼠脑组织的影响，试验采用平板菌落计数法和OD-Monitor振荡比浊法（D_λ值法）测定粪肠球菌的生长曲线，探究该菌在合适时间段内的吸光值（D_{600 nm}）与平板菌落计数法测定的活菌数（CFU）的关系。用粪肠球菌感染小鼠，观察记录小鼠的死亡情况，最后采用Karber法计算粪肠球菌感染小鼠的半数致死量（LD₅₀）。用LD₅₀的剂量感染小鼠，及时采集死亡小鼠脑组织，未死亡的小鼠72 h后全部剖杀取脑组织，一部分做涂片染色，制作病理切片，观察病理变化；一部分进行培养，用于PCR方法进行细菌的回收鉴定。结果显示，用两种方法测定此株粪肠球菌的生长曲线基本一致，在2~8 h生长迅速，为对数生长期，8~14 h生长缓慢，为稳定期，14 h之后死亡数增加，进入衰亡期；对12 h粪肠球菌D_{600 nm}与CFU的关系进行探讨，成功建立回归方程：y=20.769x-1.3422，R²=0.997；其感染小鼠的LD₅₀为7.77×10¹¹个活菌。以此剂量感染小鼠，脑组织涂片染色和培养染色，均能看到革兰氏阳性球菌；PCR结果显示，均出现了大小为112 bp的条带。对脑组织进行病理学观察发现该菌可导致脑组织充血、出血、形成微血栓，脑膜充血。通过生长曲线和其D_{600 nm}与CFU关系的建立，可实时监测粪肠球菌数量，为后期更深入研究粪肠球菌穿越血脑屏障的机制奠定重要的理论基础。     

Regulatory role of l-proline in fetal pig growth and intestinal epithelial cell proliferation

l-proline (Pro) is a precursor of ornithine, which is converted into polyamines via ornithine decarboxylase (ODC). Polyamines plays a key role in the proliferation of intestinal epithelial cells. The study investigated the effect of Pro on polyamine metabolism and cell proliferation on porcine enterocytes in vivo and in vitro. Twenty-four Huanjiang mini-pigs were randomly assigned into 1 of 3 groups and fed a basal diet that contained 0.77% alanine (Ala, iso-nitrogenous control), 1% Pro or 1% Pro + 0.0167% α-difluoromethylornithine (DFMO) from d 15 to 70 of gestation. The fetal body weight and number of fetuses per litter were determined, and the small and large intestines were obtained on d 70 ± 1.78 of gestation. The in vitro study was performed in intestinal porcine epithelial (IPEC-J2) cells cultured in Dulbecco''s modified Eagle medium-high glucose (DMEM-H) containing 0 μmol/L Pro, 400 μmol/L Pro, or 400 μmol/L Pro + 10 mmol/L DFMO for 4 d. The results showed that maternal dietary supplementation with 1% Pro increased fetal weight; the protein and DNA concentrations of the fetal small intestine; and mRNA levels for potassium voltage-gated channel, shaker-related subfamily, member 1 (Kv1.1) in the fetal small and large intestines (P < 0.05). Supplementing Pro to either gilts or IPEC-J2 cells increased ODC protein abundances and polyamine concentrations in the fetal intestines and IPEC-J2 cells (P < 0.05). In comparison with the Pro group, the combined administration of Pro and DFMO reduced the expression of ODC protein and spermine concentration in the fetal intestine, as well as the concentrations of putrescine, spermidine and spermine in IPEC-J2 cells (P < 0.05). Meanwhile, the percentage of cells in the S-phase and the mRNA levels of proto-oncogenes c-fos and c-myc were increased in response to Pro supplementation, whereas depletion of cellular polyamines with DFMO increased tumor protein p53 (p53) mRNA levels (P < 0.05). Taken together, dietary supplementation with Pro improved fetal pig growth and intestinal epithelial cell proliferation via enhancing polyamine synthesis.     

正交设计优化青蒿SRAP-PCR反应体系及引物筛选

为了建立青蒿的SRAP最佳扩增体系,并筛选出SRAP多态性引物,本研究以青蒿叶片DNA为模板,采用正交试验设计,以Mg^2+、dNTP Mix、Taq DNA聚合酶、引物和DNA模板5种因素5个水平,对青蒿SRAP反应体系进行研究。结果表明,青蒿SRAP-PCR最佳反应体系为:引物0.6μmol/L、Mg^2+2.0 mmol/L、模板DNA 5.1 ng、Taq DNA聚合酶2.0 U、dNTPs 0.25 mmol/L,总体积为25μL。各因素对扩增反应均有不同影响,其中引物浓度的影响最大,dNTPs的影响最小。运用该体系对不同种质资源的青蒿进行验证,证明该体系稳定可靠,并在30个引物组合中筛选出了25对扩增条带清晰,多态性丰富的引物组合。这一结论为今后利用SRAP标记技术进行青蒿分子遗传学研究提供了科学依据。     

乙酰羟酸合酶抑制剂类除草剂的植物抗性机制

乙酰羟酸合酶(AHAS)抑制剂类除草剂已被广泛用于农业生产,然而使用过程中可能对部分敏感农作物产生药害,因此创制对不同类别除草剂具有抗性的一系列作物新品种至关重要。本文将从AHAS抑制剂类除草剂的类别与特点、AHAS靶酶的特性及其在支链氨基酸合成中的作用、除草剂的靶标抗性与非靶标抗性机制等方面分析国内外研究现状与未来发展动态,以期为农作物除草剂抗性性状的遗传改良和开发应用提供参考。     

河北省杂粮生产现状及生产布局展望

河北省是杂粮生产大省,且种类繁多。为稳定河北省杂粮生产发展,进一步调整河北省种植业结构提供参考依据,本文总结了河北省杂粮的历史生产现状,包括面积、单产、总产以及河北省各地市杂粮的分布,试图探索杂粮的生产布局与趋势,同时针对河北省杂粮历史单产水平变化趋势,分析了造成单产变化的成因,并简单提出建议。最后提出河北省杂粮生产布局的展望,将河北省杂粮生产区域布局划分为优势主产区、战略提升区、稳步发展区三个功能区。     

New Polyketides from the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11

The species Pseudogymnoascus is known as a psychrophilic pathogenic fungus with a ubiquitous distribution in Antarctica. Meanwhile, the study of its secondary metabolites is infrequent. Systematic research of the metabolites of the fungus Pseudogymnoascus sp. HSX2#-11, guided by the method of molecular networking, led to the isolation of one novel polyketide, pseudophenone A (1), along with six known analogs (2–7). The structure of the new compound was elucidated by extensive spectroscopic investigation and single-crystal X-ray diffraction. Pseudophenone A (1) is a dimer of diphenyl ketone and diphenyl ether, and there is only one analog of 1 to the best of our knowledge. Compounds 1 and 2 exhibited antibacterial activities against a panel of strains. This is the first time to use molecular networking to study the metabolic profiles of Antarctica fungi.     

增温加氮对两种不同来源加拿大一枝黄花子一代生长的影响

为探讨模拟气候变暖(增温2℃)和大气氮沉降(4 g·m-2·a-1)对入侵植物子代生长的影响,以中国和北美两种来源的加拿大一枝黄花子一代为研究对象,研究了子一代幼苗的生长和生物量分配的响应.结果表明:(1)增温降低中国来源加拿大一枝黄花的地上生物量,但提高其根冠比,增温降低北美来源加拿大一枝黄花的根冠比;(2)与北美来源加拿大一枝黄花相比,加氮对中国来源加拿大一枝黄花叶片数、地下生物量和总生物量的促进作用更大;(3)加氮促进加拿大一枝黄花地上生物量、地下生物量和总生物量的积累,但增温减缓了这种促进作用.这些结果表明,气候变暖可能会部分抵消氮沉降对加拿大一枝黄花子一代幼苗生长的促进作用.     

杭州星级茶馆发展的SWOT分析研究

本文梳理了杭州及国内其它地区星级茶馆的概况,并运用swot分析法,阐述了杭州星级茶馆发展的优势、劣势、机遇和挑战。最后根据分析结果,提出了综合发展对策,为推动茶馆行业健康持续发展提供参考。     

1株H1N1亚型猪流感病毒的全基因组特征及其对小鼠的致病性

旨在了解河南省猪流感病毒的流行情况及其遗传进化和基因组特征。2018年4月，从河南省某一出现疑似流感症状猪群中采集鼻拭子样品150份用于分离病毒，对分离病毒的全基因组进行序列测定和分析。同时感染6周龄BALB/c小鼠，研究其对小鼠的致病性。结果显示，获得1株H1N1亚型病毒[命名为A/swine/Henan/NY20/2018（H1N1）]。遗传进化表明，其HA和NA基因属于欧亚类禽H1N1分支，PB2、PB1、PA、NP和M基因属于2009甲型H1N1分支，NS基因属于经典H1N1分支。HA蛋白的裂解位点序列为PSIQSR↓GL，具有低致病性流感病毒的分子特征，在小鼠肺和鼻甲有效复制并能引起肺组织病理学变化。本研究分离到1株3源重排H1N1亚型病毒，对小鼠呈现一定致病力，提示应进一步加强对SIV的监测。