Ca2 +对小麦种根及其根毛生长发育的影响

低浓度的CaCl2对小麦种根生长、根毛发生和生长无明显影响,高浓度的CaCl2(0.1 mol/L)对种根和根毛生长有抑制作用,但不影响根毛的发生。Ca2+专一性整合剂EGTA抑制种根生长和根毛的发生及生长,添加一定浓度的外源CaCl2,这种抑制作用可被消除。CaM抑制剂TFP(三氟拉嗪)和CPZ(氯丙嗪)对种根生长、根毛发生和生长均有抑制作用,添加外源CaM可减弱或消除这种抑制作用。     

Revealing Pathway Dynamics in Heart Diseases by Analyzing Multiple Differential Networks

Development of heart diseases is driven by dynamic changes in both the activity and connectivity of gene pathways. Understanding these dynamic events is critical for understanding pathogenic mechanisms and development of effective treatment. Currently, there is a lack of computational methods that enable analysis of multiple gene networks, each of which exhibits differential activity compared to the network of the baseline/healthy condition. We describe the iMDM algorithm to identify both unique and shared gene modules across multiple differential co-expression networks, termed M-DMs (multiple differential modules). We applied iMDM to a time-course RNA-Seq dataset generated using a murine heart failure model generated on two genotypes. We showed that iMDM achieves higher accuracy in inferring gene modules compared to using single or multiple co-expression networks. We found that condition-specific M-DMs exhibit differential activities, mediate different biological processes, and are enriched for genes with known cardiovascular phenotypes. By analyzing M-DMs that are present in multiple conditions, we revealed dynamic changes in pathway activity and connectivity across heart failure conditions. We further showed that module dynamics were correlated with the dynamics of disease phenotypes during the development of heart failure. Thus, pathway dynamics is a powerful measure for understanding pathogenesis. iMDM provides a principled way to dissect the dynamics of gene pathways and its relationship to the dynamics of disease phenotype. With the exponential growth of omics data, our method can aid in generating systems-level insights into disease progression.     

披针叶茴香对变化光环境的表型可塑性

植物对变化光环境的表型可塑性大小影响其在林下生境中分布、生长和更新。为探讨披针叶茴香在不同光环境下的整体表型可塑性及其适应机制,采用遮荫试验模拟5种光照条件(100%、52%、33%、15%和6%相对光照强度),研究了不同光环境下披针叶茴香叶片形态、生理、解剖结构、根系形态以及生物量分配等的变化。结果表明:叶生物量在5种光照处理之间差异不显著,但叶面积和比叶面积均随光照强度减弱显著增加。遮荫处理增加了叶绿素a、叶绿素b和类胡萝卜素的含量,但叶绿素a/b比值随光照强度减弱而降低。遮荫降低了非结构性碳水化合物(淀粉和可溶性糖)和可溶性蛋白的含量,增加了叶片氮和磷含量,对叶片氮/磷比影响较小。在52%和33%相对光照处理下,叶片中硝酸盐含量最低,而在100%和6%相对光照处理下硝酸盐积累较多。根生物量、细根和粗根的长度、表面积以及比根长和比根表面积在5种光照处理之间均没有显著差异,根系氮含量在低光环境(15%和6%相对光照处理)中显著降低。随光照强度减弱,披针叶茴香采取保守生存策略,并没有增加叶生物量的分配,而是分配较多的生物量给枝条和树干,储存能量。综合来看,披针叶茴香具有较宽的光生态幅,在6%—100%光照强度下均能正常生长,遮荫有利于披针叶茴香地上和总生物量的积累,52%的相对光照条件下生长最佳。变化光环境下根系性状和整体结构的可塑性相对较低,叶片生理性状的可塑性在披针叶茴香适应光环境变化过程中发挥了主要作用。     

深圳南山区天然植物群落的聚类分析

运用组平均聚类法,以44个样方中80个种的重要值为数据,对深圳南山区天然植物群落进行聚类分析。根据聚类结果,南山区天然植物群落可划分为8个群系19个群丛,较全面地反映了群落的组成结构以及群落的生境,为南山区植物群落的保护和管理提供了科学依据。     

楝科物质对亚洲玉米螟幼虫取食和生长发育的影响

近年来植物成分对昆虫行为和生长发育的影响很受人们重视。对印楝(Azadirachta indica)的研究证明其含有多种杀虫物质(Schmutterer和Ascher等,1981)。国外报道与印楝为近缘种的苦楝(Melia azadirach)也对昆虫有拒食和干扰生长发育的作用(Schmutterer,1981;Tu和Rueda等,1981),并从中分离出了多种活性物质(Cox,1981)。我国也曾研究应用苦楝防治害虫(中国土农药志编辑委员会,1959),最近证明川楝(Melia toosendan)中成分对水稻三化螟有内吸致毒和拒食作用(赵善欢和张     

密码子优化对DNA疫苗免疫原性的影响

DNA疫苗作为疫苗研制工业中的新成果已经得到了越来越多得关注。为了提高其免疫原性,发挥它最大的保护作用,人们进行了各种尝试。近几年来的研究表明,通过密码子优化的方式可以提高DNA疫苗的免疫原性,增强其免疫保护作用。本文即针对该问题做了一些总结。     

表面活性剂对嗜盐嗜碱硫碱弧菌D301生成及利用硫颗粒的影响

【背景】微生物脱硫是脱除气体中硫化氢的一种有效方法,其中,硫颗粒的生成与代谢是控制生物脱硫效率的关键,但目前相应的控制方法很少。【目的】研究不同种类表面活性剂对硫碱弧菌D301生成及利用硫颗粒的影响。【方法】通过摇床培养,利用X射线衍射、冷场发射扫描电镜、能谱分析及傅里叶红外光谱对硫颗粒进行表征。【结果】单质硫主要以S8形式存在,吐温-80和十二烷基磺酸钠(Sodium Dodecyl Sulfate,SDS)的添加对硫颗粒的形态及生成量影响明显。对照组中生成的硫颗粒呈规则球形,光滑完整,其表面附着蛋白质等生物大分子;加入0.01 g/L吐温-80后,硫颗粒呈长杆状、颗粒增大、利用速率减慢;加入0.3g/L的SDS后,硫颗粒呈短棒状、生成量减少、利用速率加快,同时延缓了硫碱弧菌D301的衰亡。【结论】添加表面活性剂可以改变硫颗粒形态并且影响其利用,是一种调控硫颗粒生成和代谢的有效手段。     

内蒙古乌海市鸟类区系特征及群落结构

2009年4月至2010年3月对内蒙古乌海市的鸟类区系及群落结构进行了调查研究。共记录到鸟类132种,隶属于17目37科。其中留鸟26种,夏候鸟71种,旅鸟27种,冬候鸟8种。繁殖鸟有97种,其中古北界鸟类有83种,占繁殖鸟类种数的85.6%。研究发现不同季节、不同生境中的鸟类群落特征差异较大。春季的鸟类多样性指数和均匀度指数均最高;湿地的鸟类多样性指数最高。本文基于研究结果提出了对乌海市鸟类及其生存环境的保护建议。     

Binding characterization of the interleukin-13 signaling complex and development of a ternary time-resolved fluorescence resonance energy transfer assay

Interleukin-13 (IL-13) is a critical mediator of pulmonary pathology associated with asthma. Drugs that block the biological function of IL-13 may be an effective treatment for asthma. IL-13 signals by forming a ternary complex with IL-13Rα1 and IL-4R. Genetic variants of IL-13 and of its receptor components have been linked to asthma. One in particular, IL-13R110Q, is associated with increased IgE levels and asthma. We characterized the interactions of the binary complexes composed of IL-13 or IL-13R110Q with IL-13Rα1 and the ternary complexes composed of IL-13 or IL-13R110Q and IL-13Rα1 with IL-4R using surface plasmon resonance and time-resolved fluorescence resonance energy transfer (TR-FRET). By both biophysical methods, we found no differences between IL-13 and IL-13R110Q binding in either the binary or the ternary complex. IL-4R bound to the IL-13/IL-13Rα1 complex with slow on and off rates, resulting in a relatively weak affinity of about 100 nM. We developed a TR-FRET assay targeting the interaction between the IL-4R and the binary complex. Two antibodies with known binding epitopes to IL-13 that block binding to either IL-13Rα1 or IL-4R inhibited the TR-FRET signal formed by the ternary complex. This assay will be useful to identify and characterize inhibitory molecules of IL-13 function.     

应用DGGE研究微生物群落时的常见问题分析

变性梯度凝胶电泳(DGGE)是通过核酸片段对微生物群落进行研究,可以监测未培养细菌及其功能基因,被广泛地应用于微生物群落多样性和动态分析,并成为微生物分子生态学研究中的重要手段之一。文中论述了DGGE操作过程中遇到的常见问题,并提出了相应的解决方法。全面分析了样品预处理过程和PCR扩增效果对DGGE分析的影响,探讨了DGGE图谱的优化过程和图谱分析方法,并对DGGE的应用前景进行了综述。