胺鲜酯对高产夏玉米产量及叶片光合羧化酶和保护酶活性的影响

采用田间小区试验,以高产玉米新品种登海661为材料,研究了拔节期叶面喷施10、20和40 mg·L^-1的胺鲜酯（DA-6）对玉米叶片光合羧化酶、保护酶活性和产量的影响.结果表明：喷施胺鲜酯各处理玉米分别比对照（含有表面活性剂和水）增产10.0%(10 mg·L^-1)、8.9%(20 mg·L^-1)和9.4%(40 mg·L^-1),增产效果显著,但各浓度间差异不显著.胺鲜酯处理后,花后玉米的叶面积指数、光合速率、RuBP羧化酶和PEP羧化酶活性均显著上升(P＜0.05),且对光合速率、RuBP羧化酶和PEP羧化酶活性的影响随着处理浓度的增加而提高;与对照相比,胺鲜酯处理后吐丝期、灌浆期、乳熟期和蜡熟期叶片SOD、CAT、POD和GSTs活性及可溶性蛋白质含量显著提高(P＜0.05),MDA含量显著降低(P＜0.05),其中CAT活性随着处理浓度的增加呈上升趋势,其余生理指标各浓度间无显著性差异.     

不同坡位下巨桉人工林土壤动物群落特征

为了解坡位对巨桉人工林土壤动物群落结构的影响,2009年1-10月,调查了四川盆地低山丘陵区不同坡位巨桉人工林的土壤动物群落.从3个巨桉人工林共获取土壤动物34741只,鉴定出146个类群,隶属于7门16纲31目;巨桉人工林下土壤动物的群落组成、营养类群、多样性及其季节动态基本都存在坡位变化,大型和中小型干生土壤动物的个体数、大型土壤动物的腐食性类群和中小型干生土壤动物的杂食性类群数量表现出随坡位的下降而逐渐增多的趋势,说明土壤动物响应了坡位引起的土壤生态因子的变化.其中大型土壤动物的腐食性类群和中小型湿生土壤动物的多样性显示出显著的坡位差异,表明这两个指标能指示巨桉人工林不同坡位生境的异质性.总的看来,巨桉人工林坡位因子对土壤动物群落的分布及结构特征具有一定影响,但作用尚不显著.     

Morphology,distribution,and chromosome counts of two varieties of Hedychium villosum(Zingiberaceae)

Polyploidy is a major mechanism of adaptation and speciation in plants.Two varieties of Hedychium villosum,var.villosum and var.tenuiflorum,primarily differ in plant and flower size.Chromosome number suggests that var.tenuiflorum is diploid(2n=34)and var.villosum is tetraploid(2n=68).Although the flowers of the two varieties do not have any difference in floral shape,each can be easily distinguished morphologically because the shoots,leaves,and flowers of the tetraploid var.villosum are consistently larger than the diploid var.tenuiflorum.The two varieties each possess distinct geographic ranges and habitats,and no sympatric distribution has been found.The tetraploid var.villosum has a broader geographic distribution range and more diverse ecological habitats than the diploid var.tenuiflorum.The two varieties are also completely reproductively isolated due to the non-overlap of their flowering times.The two varieties should be recognized as two distinct species as they fulfill the requirements of various species concepts.Thus,we suggested that the tetraploid var.villosum should be kept as Hedychium villosum and the diploid var.tenuiflorum should be renewed to Hedychium tenuiflorum.     

Tet调控CYP2E1基因表达细胞系的代谢能力分析

应用Tet-On基因表达系统,调控CYP2E1基因在NIH 3T3细胞中的表达水平,探讨CYP2E1在化学致癌物二甲基亚硝胺(N-nitrosodimethylamine, NDMA)代谢中的作用．先后将 Tet-on基因表达系统的调控质粒pRevTet-on和反应质粒pRevTRE-2E1转染NIH 3T3细胞,分别用G418和潮霉素筛选,并通过RT-PCR和Western印迹检测,成功获得了3个具有良好诱导性Tet调控的CYP2E1基因表达细胞系（Tet/3T3-2E1）．应用不同浓度强力霉素(doxycycline, Dox)处理Tet/3T3-2E1细胞诱导CYP2E1表达,HPLC分析细胞对CYP2E1特异性药物探针氯唑沙腙的原位代谢能力及MTT法分析CYP2E1介导的NDMA细胞毒性作用．结果显示,Tet/3T3-2E1细胞CYP2E1的表达及其代谢能力有明显的Dox浓度依赖性,而且NDMA对Dox诱导组细胞有明显浓度依赖性细胞毒性作用,其IC₅₀值为12.06 μmol/L,无Dox诱导组未见明显的NDMA细胞毒性作用．该细胞模型的成功建立对于开展与CYP2E1相关的毒物、致癌物代谢研究,筛选抗毒物、抗癌物等具有重要价值．     

Floral-dip转化法将PEPC基因ihpRNA干扰表达载体导入甘蓝型油菜

根据磷酸烯醇丙酮酸羧化酶(PEPC)基因控制油菜籽中蛋白质与脂肪酸合成的原理,构建了PEPC基因片段ihpRNA干扰表达载体,该载体包含了一个PEPC基因片段正反向序列的回文结构．表达RNA干扰的载体结构（ihpRNA）,在大肠杆菌体内进行克隆的过程中易被大肠杆菌自身携带的某种酶剪切,剪切位点不确定,可能是一种随机性的剪切．通过反复实验,最终获得了一个与我们设计一致的PEPC基因片段正反向序列结构, RNA干扰表达载体构建获得成功．利用花序浸渍法(floral-dip)转基因将构建的PEPC基因ihpRNA干扰表达载体转移到甘蓝型油菜中,并通过抗性筛选、PCR特异扩增、PCR-Southern杂交和克隆测序,对获得的转基因植株进行了鉴定,转化率达到了069%,说明floral-dip方法有效地实现了ihpRNA干扰表达载体的遗传转化     

游仆虫重组核糖体蛋白L11与肽链释放因子的体外相互作用分析

核糖体蛋白L11(ribosome protein L11)是一种高度保守的蛋白质．为研究真核生物的核糖体蛋白L11的功能,从八肋游仆虫（Euplotes octocarinatus）大核基因组中克隆到核糖体蛋白L11基因,构建了重组表达质粒pGEX-6p1-L11,通过谷胱甘肽-Sepharose 4B亲和层析,纯化了重组融合蛋白GST-L11．Pull down 分析显示,八肋游仆虫的核糖体蛋白L11与第一类肽链释放因子eRF1a可以在体外相互作用．这一结果提示,与原核生物一样,低等真核生物的核糖体蛋白L11在肽链终止过程中可能起一定的作用．     

Composition and antimicrobial activity of the essential oils from invasive species of the Azores,Hedychium gardnerianum and Pittosporum undulatum

The compositions of the essential oils from the leaves and flowers of Hedychium gardnerianum and from the leaves of Pittosporum undulatum growing on San Miguel Island (Azores) were investigated, and the compounds were identified by GC-MS analyses. The oils in the leaves and flowers of H. gardnerianum were rich in alpha-pinene, beta-pinene and alpha-cadinol, whereas that from P. undulatum was found to contain monoterpenes, sesquiterpenes, diterpenes and alkanes, of which the sesquiterpenes, calamenene (41.4%), farnesol (10.9%), spathulenol (5.6%) and beta-selinene (5.2%) and the diterpene (8beta,13beta)-kaur-16-ene (10.7%) were the major components. Their potential antimicrobial activities were tested against Staphylococcus aureus, S. epidermis and Pseudomonas aeruginosa, and those with the highest activities against S. aureus and S. epidermis were from H. gardnerianum; none had activity against P. aeruginosa. Additionally, the essential oils from Pittosporum undulatum had good antithrombin activity whereas that from H. gardnerianum did not.     

外源水杨酸改善Cd胁迫下路易斯安娜鸢尾的生长和养分吸收

采用Hoagland溶液培养,研究了外源水杨酸(SA)预处理对镉(Cd)胁迫下路易斯安娜鸢尾生物量、含水量、光合作用、根系活力、Cd积累、矿质养分吸收和抗氧化酶活性的影响.结果表明： Cd胁迫下,SA预处理的植株根叶干质量、根系活力和净光合速率提高.与单独Cd处理相比,SA预处理后的胁迫植株Cd含量无明显变化,而叶片N、P、S含量显著提高,K含量显著下降,根部抗氧化酶活性显著提高.表明SA预处理可明显缓解路易斯安娜鸢尾的Cd伤害,其原因不在于减少Cd吸收量而是提高了对Cd的抗性,矿质元素的吸收积累调节和根部抗氧化酶活性的提高是其毒害缓解的重要原因.