Migration and the evolution of duetting in songbirds

Many groups of animals defend shared resources with coordinated signals. The best-studied of these signals are the vocal duets produced by mated pairs of birds. Duets are believed to be more common among tropical-breeding species, but a comprehensive test of this hypothesis is lacking, and the mechanisms that generate latitudinal patterns in duetting are not known. We used a stratified sample of 372 songbird species to conduct the first broad-scale, phylogenetically explicit analysis of duet evolution. We found that duetting evolves in association with the absence of migration, but not with sexual monochromatism or tropical breeding. We conclude that the evolution of migration exerts a major influence on the evolution of duetting. The perceived association between tropical breeding and duetting may be a by-product of the migration–duetting relationship. Migration reduces the average duration of partnerships, potentially reducing the benefits of cooperative behaviour, including duetting. Ultimately, the evolution of coordinated resource-defence signals in songbirds may be driven by ecological conditions that favour sedentary lifestyles and social stability.     

Benzene-1,3-dicarboxylic acid 2,5-dimethylpyrrole derivatives as multiple inhibitors of bacterial Mur ligases (MurC–MurF)

Enzymes catalyzing the biosynthesis of bacterial peptidoglycan represent traditionally a collection of highly selective targets for novel antibacterial drug design. Four members of the bacterial Mur ligase family—MurC, MurD, MurE and MurF—are involved in the intracellular steps of peptidoglycan biosynthesis, catalyzing the synthesis of the peptide moiety of the Park’s nucleotide. In our previous virtual screening campaign, a chemical class of benzene-1,3-dicarboxylic acid 2,5-dimethylpyrrole derivatives exhibiting dual MurD/MurE inhibition properties was discovered. In the present study we further investigated this class of compounds by performing inhibition assays on all four Mur ligases (MurC–MurF). Furthermore, molecular dynamics (MD) simulation studies of one of the initially discovered compound 1 were performed to explore its geometry as well as its energetic behavior based on the Linear Interaction Energy (LIE) method. Further in silico virtual screening (VS) experiments based on the parent active compound 1 were conducted to optimize the discovered series. Selected hits were assayed against all Escherichia coli MurC–MurF enzymes in biochemical inhibition assays and molecules 10–14 containing benzene-1,3-dicarboxylic acid 2,5-dimethylpyrrole coupled with five member-ring rhodanine moiety were found to be multiple inhibitors of the whole MurC–MurF cascade of bacterial enzymes in the micromolar range. Steady-state kinetics studies suggested this class to act as competitive inhibitors of the MurD enzyme towards d-Glu. These compounds represent novel valuable starting point in the development of novel antibacterial agents.     

利用分析Unigene在转录组中表达模式的方法拼接盐角草铵转运基因

RNA-seq技术能够全面快速地获得物种在某一状态下的转录本序列信息,但测序并组装后的大量Unigene往往不包含完整ORF(Open reading frame)。转录组库具有一定的冗余性,存在着属于同一个转录本的Unigene,这些Unigene因为无重叠区不能拼接而存在转录组库中。基于这种情况,为了拼接铵转运蛋白家族Unigene,首先挑选注释为AMT(Ammonium transporter)且ORF不完整的所有Unigene(5条),通过分析Unigene在4个转录组的表达模式,其中2条Unigene(Uni4和Uni5)具有相同的表达模式,推测可能来自同一转录本。然后通过NCBI blastx将这2条Unigene与参考物种的AMT蛋白质比对,确定其在转录本的位置及序列相互间没有交叠(如果两条编码序列相互交叠则不能组成同一个转录本)。结果发现Uni4和Uni5分别位于参考转录本5′端和3′端位置,因此假定它们属于同一个转录本,中间空缺约120 bp未知序列。通过试验验证,分别在Uni4和Uni5上设计单正向引物和单反向引物,PCR扩增得到约800 bp片段,将其测序并与两条Unigene比对,证实Uni4和Uni5属于同一转录本且获得了缺失的未知序列。最终拼接得到1 667 bp序列,包含1 482 bp完整ORF,编码494个氨基酸,通过系统进化分析将其归类为amt1亚家族,命名为Seamt1。生物信息学手段预测Se AMT1蛋白与已知的其他物种AMT性质相似。本研究采用转录组Unigene表达模式聚类的方法挖掘潜在的同一转录本Unigene,并且通过另外两组Unigene检验了该方法的可行性。这一便捷方法有助于转录组中Unigene的延伸和拼接,有助于完整ORF的获得及后期基因功能研究。     

血管内皮生长因子(VEGF)乳液法电纺纤维膜的体外研究

目的:研究担载血管内皮生长因子(VEGF)的乳液法电纺纤维膜的亲水性能、外观形态和机械性能,纤维膜中VEGF的包封率和体外释放动力学,为评价其能否应用于血管再生领域的研究奠定基础。方法:将VEGF水溶液通过W/O乳液法制备成缓释VEGF的生物可降解的丙交酯-乙交酯共聚物(PLGA)静电纺丝纤维膜,对该纤维膜的接触角、外观形态、机械性能进行表征,Elisa法测定该纤维膜的体外14天的释放行为,分别观察纤维膜释放0天、7天、14天后的电镜图。结果:加入VEGF后,纤维膜的接触角由140.0°减小到136.1°,亲水性增强,具有类似细胞外基质(ECMs)网状结构和良好的力学性能,纤维膜第1天的突释不超过载药量的50%,电镜图下显示纤维膜释放1周时纤维发生断裂。结论:通过乳液法制备的担载VEGF的电纺纤维膜具有良好的物理性能,能够持续缓释VEGF,可作为血管再生的组织工程支架进行深入研究。     

自由体位分娩加分娩减痛法在初产顺产妇中的临床应用效果

目的:研究和探讨自由体位分娩法和分娩减痛法结合起来在初产顺产妇中的临床应用效果。方法:选取2013年1月至2013年12月已被收治的符合标准的初产顺产妇女360例为研究对象,将其随机分成A1组(自由体位分娩法组)、A2组(分娩减痛法组)和A1+A2组(两种方法结合组),每组120例。观察和比较三组产妇阴道分娩产程时间、疼痛等级评分、出血量、剖宫产率、新生儿Apgar评分情况和产后不良情况发生率。结果:①A1+A2组的分娩产程时间低于A1组及A2组,疼痛等级评分优于A1组和A2组(P均0.05);②A1+A2组的分娩过程中的出血量和剖宫产率均低于A1组及A2组(P0.05);③A1+A2组新生儿Apgar评分情况比A1组及A2组好(P0.05);④A1+A2组产后不良情况的发生率也低(P0.05)。然而以上观察指标A1组与A2组之间的差异均无统计学意义(P0.05)。结论:在临床实践过程中对初产顺产产妇实施自由体位分娩结合分娩减痛法可以显著地改善产妇分娩过程中的不良情况,对新生儿的影响也是积极的。两种方法的综合应用更具有良好的临床效果。     

A model for developing a target integrated low carbon city indicator system: The case of Xiamen,China

Carbon intensity targets, namely carbon emissions per unit of GDP, are used as macro-level indicators of low carbon performance at the province- and city-level in China. However, this measure is too aggregated to provide a meaningful indication of low carbon performance and inform practical management strategies. Most traditional low carbon city indicators have no direct relationship with national carbon intensity reduction targets and do not provide municipal government administrators with the practical information they need to inform low carbon development at the local level. This paper integrates city-level carbon intensity targets with a low carbon city indicator system by means of a decomposed method to offer a better approach for carbon intensity reduction performance evaluation. Using Xiamen as a case study, one of the NDRC's low-carbon project areas, a target integrated indicator system is presented, including indicator values which have been determined through scenario analysis and calculation. The indicators and values can help local municipal governments to meet their carbon intensity reduction targets by providing an indication of current performance and identifying sectors where there is scope for further improvement. The methodology provides the theoretical basis and reference values for the evaluation of a city's low carbon performance within the context of achieving a carbon reduction target, thereby enhancing the potential for scientific and operational evaluation at the local level.     

Structural and photoluminescence study of Mn2+‐activated CaYAl3O7 blue phosphors

The structural and photoluminescence properties of CaYAl₃O₇ phosphor material doped with varying concentration of Mn²⁺ have been studied. The phosphor material was synthesized by the combustion method at 500 °C and was characterized using X‐ray diffraction, Fourier transform infrared spectroscopy and photoluminescence spectroscopy (PL). X‐ray diffraction showed that the crystallites have average sizes in the range of ~58–70 nm. Corresponding Fourier transform infrared spectroscopy investigations confirm the phase formation and the presence of aluminate group (Al‐O bands) in CaYAl₃O₇:Mn²⁺ phosphor. Under the excitation at 356 nm wavelength, the PL spectra show the occurrence of two emission peaks obtained in the blue region at 389 nm and 412 nm, which is attributed to the 4 T1(G) → 6A1 transition of Mn²⁺ ion. Upon increasing Mn²⁺ concentration, the relative PL intensity shows an initial decrement followed by an increase displaying the effect of concentration quenching. Overall the results suggest the possibility of using this material in white lighting devices and plasma display panels. Copyright © 2013 John Wiley & Sons, Ltd.     

Ca3(PO4)2:Eu3+ phosphor preparation with different morphologies and their fluorescence properties

Ca₃(PO₄)₂:Eu³⁺ phosphor was prepared using a facile chemistry method in the presence of surfactants. The effects of surfactants on the morphology and photoluminescence properties of Ca₃(PO₄)₂:Eu³⁺ phosphor were investigated. The morphology of the phosphor was significantly influenced by the surfactants employed. When nonionic surfactant glyceryl monostearate and anionic surfactant sodium dodecylbenzene sulfonate were employed, the phospor powders are composed of a large number of homogeneous spherical particles with sizes of 0.3–0.6 µm and 2–3 µm, respectively. By contrast, when cationic surfactant cetyltrimethylammonium bromide was used, the morphology of the phosphor is completely different. The product is an excellent cuboid, and the phosphor prepared with 2.5 mmol cetyltrimethylammonium bromide showed higher luminescent intensity than phosphors prepared with the other two types of surfactants. Copyright © 2013 John Wiley & Sons, Ltd.