射干叶中异黄酮类化学成分的研究

从海南产射干叶中分得8个异黄酮类化合物,通过理化常数测定和光谱分析其化学结构分别鉴定为鸢尾黄酮新苷A(iristectorin A,1)、野鸢尾苷(iridin,2)、鸢尾苷(tectoridin,3)、鸢尾苷元(tectorigenin,4)、次野鸢尾黄素(irisflorentin,5)、染料木素(genistein,6)、染料木苷(genistin,7)、樱黄素(Prunetin,8)。所有化合物均为首次从射干叶中分离得到,其中化合物7和8为首次从鸢尾科植物中分离。     

Ecophysiological controls over the net ecosystem exchange of mountain spruce stand. Comparison of the response in direct vs. diffuse solar radiation

Cloud cover increases the proportion of diffuse radiation reaching the Earth's surface and affects many microclimatic factors such as temperature, vapour pressure deficit and precipitation. We compared the relative efficiencies of canopy photosynthesis to diffuse and direct photosynthetic photon flux density (PPFD) for a Norway spruce forest (25‐year‐old, leaf area index 11 m² m⁻²) during two successive 7‐day periods in August. The comparison was based on the response of net ecosystem exchange (NEE) of CO₂ to PPFD. NEE and stomatal conductance at the canopy level (G_canopy) was estimated from half‐hourly eddy‐covariance measurements of CO₂ and H₂O fluxes. In addition, daily courses of CO₂ assimilation rate (A_N) and stomatal conductance (G_s) at shoot level were measured using a gas‐exchange technique applied to branches of trees. The extent of spectral changes in incident solar radiation was assessed using a spectroradiometer. We found significantly higher NEE (up to 150%) during the cloudy periods compared with the sunny periods at corresponding PPFDs. Prevailing diffuse radiation under the cloudy days resulted in a significantly lower compensation irradiance (by ca. 50% and 70%), while apparent quantum yield was slightly higher (by ca. 7%) at canopy level and significantly higher (by ca. 530%) in sun‐acclimated shoots. The main reasons for these differences appear to be (1) more favourable microclimatic conditions during cloudy periods, (2) stimulation of photochemical reactions and stomatal opening via an increase of blue/red light ratio, and (3) increased penetration of light into the canopy and thus a more equitable distribution of light between leaves. Our analyses identified the most important reason of enhanced NEE under cloudy sky conditions to be the effective penetration of diffuse radiation to lower depths of the canopy. This subsequently led to the significantly higher solar equivalent leaf area compared with the direct radiation. Most of the leaves in such dense canopy are in deep shade, with marginal or negative carbon balances during sunny days. These findings show that the energy of diffuse, compared with direct, solar radiation is used more efficiently in assimilation processes at both leaf and canopy levels.     

甲氧虫酰肼对棉铃虫生长发育的亚致死效应研究

以一个对甲氧虫酰肼具有18.5倍抗性的棉铃虫Helicoverpa armigera(Hübner)种群(R)和其同源对照种群(S)为对象,研究了甲氧虫酰肼对棉铃虫生长发育的亚致死效应。结果表明,甲氧虫酰肼亚致死剂量(LC25)处理R和S种群的3龄初幼虫,对S种群幼虫的生长抑制率(37.30%)显著大于R种群(21.20%)。与空白对照处理相比,致死剂量处理R和S种群后,均表现出生长发育延缓,蛹期延长,化蛹率、羽化率、卵孵化率降低,且对S种群的影响更明显。研究结果表明亚致死剂量的甲氧虫酰肼对棉铃虫存在一定的不利影响,但对甲氧虫酰肼具有一定抗性的棉铃虫种群能够减轻这种不利影响。     

Molecular phylogeny and divergence times of Hormaphidinae (Hemiptera: Aphididae) indicate Late Cretaceous tribal diversification

The aphid subfamily Hormaphidinae is a good candidate for the study of the evolution of insect – plant relationships. Most hormaphidine species depend on woody primary host plants and woody or herbaceous secondary host plants, and represent high host specificity, especially to their primary hosts. No detailed molecular phylogeny of Hormaphidinae has been reported, and the taxonomic positions of some taxa in this group remain unclear. To reconstruct major phylogenetic relationships and to understand the evolution of host association patterns for major lineages, we present the first detailed molecular phylogeny of Hormaphidinae, as inferred from nuclear and mitochondrial DNA sequences, using maximum parsimony, maximum likelihood, and Bayesian methods. The monophyly of Hormaphidinae and its three traditional tribes was supported, and a sister relationship between Hormaphidini and Nipponaphidini was suggested. Most inner relationships within tribes were also supported, and some novel relationships were revealed. Two subtribes of Cerataphidini are proposed. Divergence times estimated using a Bayesian approach indicate that tribal diversifications occurred during the Late Cretaceous and were coincident with the appearance of their primary host plants. The current pattern of secondary host association for the three tribes may have evolved in different time ranges. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 73–87.     

海南岛象耳豆根结线虫的种类鉴定及其rDNA-ITS序列分析

【背景】植物根结线虫病是世界性分布的土传病害,常造成农作物的重大经济损失。目前分布于热带亚热带区域的象耳豆根结线虫,由于其致病性和分子特征以及与植物互作关系的独特性,被认为是一种对农作物具有潜在危害性的重要病原根结线虫,因而引起国内外植物寄生线虫学者的广泛关注。【方法】用形态学、同工酶技术和分子生物学技术相结合的方法,对从海南岛农作物上采集到的10个根结线虫纯化种群进行分类鉴定。【结果】象耳豆根结线虫在海南岛大面积栽培的10种农作物和南药植物,包括黄瓜、南瓜、苦瓜、丝瓜、葫芦瓜、辣椒、番石榴、海巴戟、沈香和丁香上均有寄生,其形态学、酯酶表型和mtDNA-PCR扩增产物均有别于常见的根结线虫种类;用引物18S和28S扩增象耳豆根结线虫种群的rDNA-ITS区序列,并对其进行克隆、测序和比对分析,结果表明,象耳豆根结线虫4HBJ种群分别与南方根结线虫、爪哇根结线虫和花生根结线虫的同源性均仅为88%左右。【结论与意义】本文准确鉴定了象耳豆根结线虫,首次阐述其对海南岛多种农作物的致害性;阐释了象耳豆根结线虫的形态和分子特征,并明确了其与3种常见根结线虫的系统发育关系。本研究对今后进一步开展象耳豆根结线虫的基础研究和防治工作具有重要参考价值。     

椭圆背角无齿蚌胃的组织学及铜对其结构的影响

硫酸铜常用于水产养殖的疾病防治,但当水体中的铜离子浓度超过一定范围时便对软体动物产生一定的毒害作用.研究选取椭圆背角无齿蚌(Anodonta woodiana elliptica)作为研究对象,采用苏木精-伊红染色方法进行组织石蜡切片制作,从组织学角度研究了浓度为0.01 mg·L^-mg·L^-1、0.1 mg·L^-1、1 mg·L^-1和10 mg·L^-1的硫酸铜作用不同时间后椭圆背角无齿蚌的胃结构的变化.结果表明,0.01 mg·L^-1硫酸铜处理7d和14d后,仅胃绒毛变短,随着硫酸铜浓度的增大和处理时间的延长,胃绒毛逐渐变短,肌层变薄,腺细胞数量减少直至空化;低于10mg·L^-1的硫酸铜中毒7d和14d后,胃晶杆头直径和胃楯长度出现增大的现象.     

CKLFSF1基因与CKLFSF2基因间存在的顺式作用元件

探讨趋化素样因子超家族成员 1,2基因 (CKLFSF1基因与CKLFSF2基因 )间的短序列对其下游基因表达的调控作用 .运用PCR技术扩增CKLFSF1基因与CKLFSF2基因间的序列 ,将此片段插入含有萤光素酶 (luciferase)报告基因载体上 .以磷酸钙介导基因转染技术 ,将重组质粒以及阴性和阳性对照组质粒转染到HeLa细胞 ,进行瞬时表达分析 .在pGL3 Basic质粒中的报告基因萤光素酶无表达 ,但将CKLFSF1与CKLFSF2基因间的序列插入到启动子上游或下游后 ,显著抑制其下游基因的表达 ,萤光素酶活性明显降低 .结果提示 ,CKLFSF1与CKLFSF2基因间的序列不具有启动子活性 ,但是该序列对其下游基因表达具有负调控作用     

Bt棉与常规棉根际土壤Bt毒蛋白和植物激素变化动态

通过ELISA法对常规棉（石远321）和转基因抗虫棉（99B、SGK321）根际土壤苏云金芽孢杆菌（Bt）毒蛋白和植物激素含量进行了分析,结果表明抗虫棉根际土壤Bt毒蛋白含量显著高于常规棉,特别是从苗期到盛花期抗虫棉根际土壤Bt毒蛋白含量高出常规棉200-300ng／g。抗虫棉根际土壤中脱落酸（ABA）和生长素吲哚乙酸（IAA）含量变化趋势与常规棉相比表现出较大差异。常规棉与抗虫棉根际土壤中ABA变化趋势表现为相似的单峰曲线,而抗虫棉根际土壤中ABA含量变化幅度明显小于常规棉。在棉花生长发育后期抗虫棉根际土壤中赤霉酸（GA3）含量较高,而常规棉根际土壤中GA,含量升高较抗虫棉早且变化幅度大,在高峰处常规棉高于抗虫棉,低谷时抗虫棉高于常规棉。7月17日常规棉根际土壤IAA含量显著高于抗虫棉,8月27日抗虫棉又大大高于常规棉,其他时期变化不大。上述结果表明,外源Bt基因的插入或表达能引起棉花根际土壤中Bt毒蛋白和植物激素含量的较大改变,这种改变可能会影响到抗虫棉的生长发育,并对环境产生影响。     

棉铃虫幼虫神经细胞的急性分离培养及其电压门控通道的膜片钳研究

探索了棉铃虫Helicoverpa armigera幼虫神经细胞的急性分离与体外培养的条件,并利用全细胞膜片钳技术首次对棉铃虫幼虫急性分离神经细胞的电压门控性钠、钾和钙通道的基本电生理学特性进行了研究。结果表明,棉铃虫幼虫中枢神经细胞在TC-100、L-15和Grace培养基中均可贴壁生长,在DMEM培养基中基本不能存活。在TC-100培养基分别与其它三种培养基按一定比例混合形成的培养液中,TC-100与L-15等量混合培养液更适合于神经细胞的生长。全细胞电压钳条件下,可分别记录到电压门控性钠、钾和钙通道电流。钙电流特征为高电压激活、缓慢失活;钠电流对河豚毒素敏感;钾电流可被细胞外液中的氯化四乙胺和4-氨基吡啶抑制。     

利用宿主-载体平衡致死系统构建志贺氏菌3价疫苗候选株

选择福氏2a志贺氏菌疫苗株T32为受体菌,通过基因同源重组交换技术,对其染色体asd基因进行定位突变,使之不能在LB培基上生长;同时利用链球菌asd基因构建Asd⁺的无抗药性互补载体,两者组成1套T32宿主载体平衡致死系统.进一步应用该系统克隆和表达了具有重要免疫保护功能的宋内I相O抗原基因和志贺氏毒素B亚单位基因(stxB),构建成福氏2a-宋内-StxB3价菌苗候选株FSD0l.结果显示:该菌株遗传稳定,重组质粒不需用抗生素选择,能有效表达3价抗原和产生针对上述3种野生型毒株的免疫保护反应.