Coloration and phenology manifest nutrient variability in senesced leaves of 46 temperate deciduous woody species

颜色和物候表明46种温带落叶木本植物衰老叶片的养分变异 不同共生植物的叶片养分含量差异显著,反映了不同的叶片养分利用策略。然而,衰老叶片养分的种间变异及其驱动因素尚不清楚。本研究旨在探讨衰老叶片养分的种间变异及其驱动因素。我们在中国东北的帽儿山森林生态系统研究站测定了46种共存温带落叶木本植物新鲜落叶的碳、氮、磷浓度。 采用随机森林模型量化10个生物因素(菌根类型、固氮类型、生长形态、耐阴性、叶片质地、变色程度、变色类型、叶片变色峰期、落叶峰期和落叶末期)的相对重要性。研究结果表明,落叶氮浓度种间变化为4倍,磷浓度变化达9倍。较高的氮和磷平均浓度(15.38和1.24 mg g⁻¹)表明该森林氮和磷限制较弱。功能群仅对特定养分及其比值有显著影响。磷浓度、氮磷比与外生菌根树种的落叶高峰日和落叶结束日呈负相关。颜色鲜艳的叶片(红色＞棕色＞黄色＞黄绿色＞绿色)倾向于比绿色叶片氮和磷浓度更低而碳氮比和碳磷比较高。随机森林模型表明,秋季叶变色和落叶物候贡献了80%的种间变异解释量。这些结果增加了我们对温带森林木本植物营养策略之衰老叶片养分变异性的理解。     

Increased anxiety-like behavior and enhanced synaptic efficacy in the amygdala of GluR5 knockout mice

GABAergic transmission in the amygdala modulates the expression of anxiety. Understanding the interplay between GABAergic transmission and excitatory circuits in the amygdala is, therefore, critical for understanding the neurobiological basis of anxiety. Here, we used a multi-disciplinary approach to demonstrate that GluR5-containing kainate receptors regulate local inhibitory circuits, modulate the excitatory transmission from the basolateral amygdala to the central amygdala, and control behavioral anxiety. Genetic deletion of GluR5 or local injection of a GluR5 antagonist into the basolateral amygdala increases anxiety-like behavior. Activation of GluR5 selectively depolarized inhibitory neurons, thereby increasing GABA release and contributing to tonic GABA current in the basolateral amygdala. The enhanced GABAergic transmission leads to reduced excitatory inputs in the central amygdala. Our results suggest that GluR5 is a key regulator of inhibitory circuits in the amygdala and highlight the potential use of GluR5-specific drugs in the treatment of pathological anxiety.     

玉米T型细胞质雄性不育系与相应保持系线粒体蛋白质组中的差异蛋白

利用固相pH3—10梯度双向凝胶电泳．对玉米T型细胞质雄性不育系（T—CMS）及其相应保持系叶片（苗期、拔节期、孕穗期）,胚轴,胚根和花药（花粉母细胞减数分裂期、花粉粒小孢子单-双核期）线粒体蛋白质组中的差异蛋白进行分析。PDQuest2D图像软件分析表明,苗期和拔节期叶片约有150个蛋白质斑点,胚轴和胚根中可识别出150个线粒体蛋白质斑点,花药中约有100个斑点。利用MALDI—TOF—MS方法．运用MASCOT软件于NCBI进行数据查询．对T—CMS与相应保持系中存在的差异蛋白进行归属鉴定,在T—CMS中存在,保持系中缺失的线粒体蛋白质有：r40cl protein（胚轴中）,mature anther—specific protein,DNA—directed RNA polymerase 23kD subunit．hexokinaseⅡ和T—CMS中缺失而在保持系中存在的有：glutathione S—transferase．putative protein。其中T—CMS与相应保持系间．线粒体蛋白质组呈现出差异的组织有胚轴、胚根和小孢子单-双核期的花药。叶片的不同发育时期线粒体蛋白质组呈现明显变化．但T—CMS与保持系间没有差异。在小孢子单-双核期（花粉败育期）的花药中,T—CMS与保持系间线粒体蛋白质组出现明显差异,线粒体蛋白质组出现变异的时期与花粉败育时期相一致。     

Evidence that the V832M E-cadherin germ-line missense mutation does not influence the affinity of alpha -catenin for the cadherin/catenin complex

Mutations in E-cadherin are associated with a number of diseases, and have been shown to contribute to disease progression. In particular, 50% of hereditary diffuse gastric cancer cases have inactivating mutations in the E-cadherin gene. An interesting mutation near the beta-catenin-binding site on the cytoplasmic domain of E-cadherin (V832M) was recently reported that produces full-length protein, but exhibits decreased binding of alpha -catenin to the cadherin/catenin complex. The study was done by transfecting mutant E-cadherin into Chinese hamster ovary fibroblast cells. Here we show that the previously reported characteristics of this mutation do not apply to human epithelial cells expressing this mutant protein and suggest that the mechanism whereby the V832M mutation in human E-cadherin promotes gastric cancer is not yet understood.     

Development of functional antibodies against influenza B virus by activation-induced cytidine deaminase in hybridoma cells

Highlights
1. Class-switch recombination was mimicked in hybridomas through a controllable expression system of activation-induced cytidine deaminase.
2. IgG antibodies were generated through this system in an anti-Flu B IgM hybridoma 7G1.
3. IgG1 and IgG2a subtypes of 7G1 present improved antiviral activity in vitro and in vivo.     

Multi‐year stigmatic pollen‐load sampling reveals temporal stability in interspecific pollination of flowers in a subalpine meadow

Co‐flowering plants may commonly experience interspecific pollination. It remains unknown, however, whether interspecific pollination is a largely stochastic process or consistent enough over years to exert selection for traits that can reduce interspecific pollination or ameliorate its deleterious effects on reproduction. To assess the likelihood of this precondition being met, stigmatic pollen loads on 17–34 insect‐pollinated plant species over three consecutive years were scored in a subalpine meadow in southwestern China. Plant species varied significantly in the amount and proportion of heterospecific pollen (HP) on stigmas. Both the number of HP species and the proportion of the pollen load that was HP for each recipient species correlated positively between years (reflected in pairwise correlations for all year‐by‐year combinations). Although inter‐annual variation was smaller for conspecific pollen (CP) than for HP loads, species tended to experience either consistently high or consistently low HP proportions across years. We found that species with higher stigmatic HP proportions generally experienced lower proportional variation in stigmatic HP, an unexpected result if high HP loads are the result of rare stochastic events. The novel finding of between‐year consistency in stigmatic loads of heterospecific pollen suggests that adaption to stigmatic loads of HP is possible, and two divergent strategies may have evolved: HP avoidance and HP tolerance. The observation of temporally consistent differences among species in levels of HP supports the idea that natural selection may be operating either to increase tolerance or to minimize arrival of heterospecific pollen on stigmas in co‐flowering plants. Such adaptations may be important for the maintenance of high levels of local plant diversity in biodiversity hotspots such as our study area.     

副溶血弧菌SH112株OmpA蛋白的高效表达及免疫学特性

【目的】我们前期研究表明副溶血弧菌SH112株的OmpA蛋白在该菌的致病过程中发挥重要作用,是亚单位疫苗研制的潜在靶标抗原。本研究进一步对ompA(VPA1186)基因进行克隆表达,并研究其免疫学特性。【方法】扩增去除信号肽序列的成熟外膜蛋白OmpA的基因片段,定向克隆至表达载体,基因测序后对其编码蛋白质进行生物信息学分析。重组蛋白His-OmpA经纯化后,免疫ICR小鼠制备鼠多抗血清。Western blotting检测该蛋白的免疫原性及鼠多抗血清的特异性。动物实验验证其免疫保护率。【结果】成功表达分子量约为40.0 kDa的重组蛋白His-OmpA。制备的鼠多抗血清ELISA效价可达1∶50000以上。Westernblotting检测结果显示,该血清可与His-OmpA蛋白、总外膜蛋白和全菌蛋白发生特异性反应,说明所表达的目的蛋白保持原蛋白的免疫原性。此外,该高免血清可与其他主要血清型的副溶血弧菌发生特异性交叉反应,而与其他非副溶血弧菌菌株无交叉反应,表明该血清特异性较高,且提示OmpA蛋白可能是副溶血弧菌属的共同保护性抗原。小鼠免疫保护实验结果表明,该蛋白可提供约35%的免疫保护率。【结论】OmpA蛋白可作为诊断副溶血弧菌感染和亚单位疫苗研制的靶蛋白,为进一步开展该蛋白的功能研究提供了参考。     

Repellent action and contact toxicity mechanisms of the essential oil extracted from Chinese chive against Plutella xylostella larvae

Botanical pesticides play increasingly important roles in the control of agricultural pests. In this study, the insecticidal effects, specifically the repellent action and contact toxicity, of the essential oil extracted from Chinese chive (EOC) against Plutella xylostella larvae were confirmed. The mechanisms of repellent’s action were studied using electroantennograms (EAGs), and the effects on glutathione S‐transferase (GST), carboxylesterase (CarE), and acetyl cholinesterase were investigated after EOC treatments. The EOC affected the EAG results and inhibited the activities of GST and CarE in treated P. xylostella larvae, which could explain its insecticidal effects. And, four pyrazines showed greater repellent activities than that of the EOC, which was confirmed as the main active compounds of EOC.