Developmental characteristics of AMPA receptors in chick lumbar motoneurons

Ca2+ fluxes through ionotropic glutamate receptors regulate a variety of developmental processes, including neurite outgrowth and naturally occurring cell death. In the CNS, NMDA receptors were originally thought to be the sole source of Ca2+ influx through glutamate receptors; however, AMPA receptors also allow a significant influx of Ca2+ ions. The Ca2+ permeability of AMPA receptors is regulated by the insertion of one or more edited GluR2 subunits. In this study, we tested the possibility that changes in GluR2 expression regulate the Ca2+ permeability of AMPA receptors during a critical period of neuronal development in chick lumbar motoneurons. GluR2 expression is absent between embryonic day (E) 5 and E7, but increases significantly by E8 in the chick ventral spinal cord. Increased GluR2 protein expression is correlated with parallel changes in GluR2 mRNA in the motoneuron pool. Electrophysiological recordings of kainate-evoked currents indicate a significant reduction in the Ca2(+)-permeability of AMPA receptors between E6 and E11. Kainate-evoked currents were sensitive to the AMPA receptor blocker GYKI 52466. Application of AMPA or kainate generates a significant increase in the intracellular Ca2+ concentration in E6 spinal motoneurons, but generates a small response in older neurons. Changes in the Ca(2+)-permeability of AMPA receptors are not mediated by age-dependent changes in the editing pattern of GluR2 subunits. These findings raise the possibility that Ca2+ influx through Ca(2+)-permeable AMPA receptors plays an important role during early embryonic development in chick spinal motoneurons.     

Ginsenoside Rb3 attenuates skin flap ischemia-reperfusion damage by inhibiting STING-IRF3 signaling

Journal of Molecular Histology - We investigate the protective effect of ginsenoside Rb3 on skin flap microvasculature following ischemia-reperfusion (I/R) injury and its regulatory mechanism. We...     

Downregulation of GluA2 AMPA Receptor Subunits Reduces the Dendritic Arborization of Developing Spinal Motoneurons

AMPA receptors lacking the GluA2 subunit allow a significant influx of Ca²⁺ ions. Although Ca²⁺-permeable AMPA receptors are a familiar feature at early stages of development, the functional significance of these receptors during the maturation of the nervous system remains to be established. Chicken lumbar motoneurons express Ca²⁺-permeable AMPA receptors at E6 but the Ca²⁺ permeability of AMPA receptors decreases ∼3-fold by E11. Considering that activity-dependent changes in intracellular Ca²⁺ regulates dendritic outgrowth, in this study we investigated whether downregulation of GluA2 expression during a critical period of development alters the dendritic arborization of spinal motoneurons in ovo. We use an avian replication-competent retroviral vector RCASBP (B) carrying the marker red fluorescent protein (RFP) and a GluA2 RNAi construct to downregulate GluA2 expression. Chicken embryos were infected at E2 with one of the following constructs: RCASBP(B)-RFP, RCASBP(B)-RFP-scrambled RNAi, or RCASBP(B)-RFP-GluA2 RNAi. Infection of chicken embryos at E2 resulted in widespread expression of RFP throughout the spinal cord with ≥60% of Islet1/2-positive motoneurons infected, resulting in a significant reduction in GluA2 protein expression. Downregulation of GluA2 expression had no effect on the dendritic arborization of E6 motoneurons. However, downregulation of GluA2 expression caused a significant reduction in the dendritic arborization of E11 motoneurons. Neither motoneuron survival nor maturation of network activity was affected by changes in GluA2 expression. These findings demonstrate that increased GluA2 expression and changes in the Ca²⁺ permeability of AMPA receptors regulate the dendritic arborization of spinal cord motoneurons during a critical period of development.     

Functional non-homologous end joining patterns triggered by CRISPR/Cas9 in human cells

正CRISPR/Cas9-mediated genome engineering technologies are now widely applied in various organisms,including mouse and human cells(Cong et al.,2013;Mali et al.,2013;Yang et al.,2013;Hsu et al.,2014).The most widely used customized CRISPR/Cas9(Sp Cas9)is derived from Streptococcus pyogenes(Cong et al.,2013).The CRISPR/Cas9 system creates site-specific double-     

华南农区典型植物的他感作用研究

研究华南农业区典型植物的他感作用,结果表明,用萝卜作生测受体时地上部水浸出物表明有他感作用的植物有拧檬按、隆缘按、赤按、木麻黄、茶、蟛蜞菊、胜红蓟、三叶鬼针草、香芳、马唐、马占相思、马尾松、蕃茄等,但无明显他感作用的有白茅、铺地木兰、凤尾竹、大叶桉、糖蜜草。研究表明柠檬桉、蟛蜞菊、胜红蓟的地上部挥发物和地部分泌物都有他感作用。木麻黄、茶、蟛蜞菊地上部水浸出物有自毒作用,花生、大豆、绿豆发芽中分泌出的物质也有自毒作用。三叶鬼针革、胜红蓟、香芳、蟛蜞菊、柠蒙桉和木麻黄地上部水浸物他感作用强度一般随着浓度而加剧,但低浓度下常表现有促进作用。三叶鬼针草水提物及柠檬桉地上部挥发物的他感效应强度与采集前一个月降雨量呈显著负相关。木麻黄小枝他感作用物浓度与温度有交互效应。柠檬桉的水浸提物在土壤中易随水流失而挥发物却易被土壤吸附。在土壤中柠檬棕叶的他感作用效应随时间成负指数减少,蟛蜞菊在土壤分解后的残留率与残留物的他感效应指数绝对值显著正相关。他感成份的分离鉴定结果表明,茶叶他感作用的主要成份为茶多酚与咖啡因,木麻黄小枝他感物中分离出五种黄酮类化合物和一种阿魏酸,胜红蓟地上部分离出胜红蓟素和一种豆甾醇。     

Quality Assessment of Clinical Practice Guidelines on the Treatment of Hepatocellular Carcinoma or Metastatic Liver Cancer

Objectives

To assess the quality of the currently available clinical practice guidelines (CPGs) for hepatocellular carcinoma, and provide a reference for clinicians in selecting the best available clinical protocols.

Methods

The databases of PubMed, MEDLINE, Web of Science, Chinese Biomedical Literature database (CBM), China National Knowledge Infrastructure (CNKI), WanFang, and relevant CPGs websites were systematically searched through March 2014. CPGs quality was appraised using the Appraisal of Guidelines for Research & Evaluation (AGREE) II instrument, and data analysis was performed using SPSS 13.0 software.

Results

A total of 20 evidence-based and 20 expert consensus-based guidelines were included. The mean percentage of the domain scores were: scope and purpose 83% (95% confidence interval (CI), 81% to 86%), clarity of presentation 79% (95% CI, 73% to 86%), stakeholder involvement 39% (95% CI, 30% to 49%), editorial independence 58% (95% CI, 52% to 64%), rigor of development 39% (95% CI, 31% to 46%), and applicability 16% (95% CI, 10% to 23%). Evidence-based guidelines were superior to those established by consensus for the domains of rigor of development (p<0.001), clarity of presentation (p = 0.01) and applicability (p = 0.021).

Conclusions

The overall methodological quality of CPGs for hepatocellular carcinoma and metastatic liver cancer is moderate, with poor applicability and potential conflict of interest issues. The evidence-based guidelines has become mainstream for high quality CPGs development; however, there is still need to further increase the transparency and quality of evidence rating, as well as the recommendation process, and to address potential conflict of interest.     

水体铜污染对苦草生长及叶绿素荧光特性的影响

该文以苦草(Vallisneria natans)为材料,研究了不同浓度铜污染水体对其叶/根长、生物量、光合色素含量、体内重金属含量及叶绿素荧光参数的影响。结果表明:随着水体铜浓度的增加,苦草的叶长、根长、生物量均显著下降;光合色素含量逐渐下降,其中叶绿素a比叶绿素b下降明显,类胡萝卜素下降幅度最小;叶片铜含量随铜浓度的增加显著上升(P0.05),各处理组根铜含量没有显著性差异,在水中铜低于0.5mg·L-1的环境中苦草具有正常的光合活性。除0.5 mg·L-1处理组外,最大荧光(Fm)、最大光化学效率(Fv/Fm)、潜在光化学效率(Fv/Fo)、光化学淬灭系数(qP)与有效量子产量[Y(Ⅱ)]均比对照组显著降低(P0.05),而非光化学淬灭效率(qN)、调节性能量耗散的量子产量[Y(NPQ)]、非调节性能量耗散的量子产量[Y(NO)]均呈上升趋势,其中Fv/Fo对铜污染反应最为灵敏。综合各参数变化情况,随着水体铜浓度的增加,苦草生长受到抑制,叶片利用光能的效率下降,PSⅡ反应中心的电子传递受到明显的抑制;苦草通过自身调节以热的形式将过剩光能耗散,以减轻PSⅡ反应中心受伤害的程度;苦草是铜超富集植物,其可作为低浓度铜污染水体生态修复的备选物种。     

铕标记抗癌胚抗原单克隆抗体C17的研究和应用

用合成的N′-(对-异硫氰基苄基)-二乙三胺-N¹,N²,N³,N³-四乙酸铕钠为螫合剂.用Sephadex G-50凝胶柱层析分离标记C₁₇和过量试剂.分部收集的层析物的光密度图和荧光强度图完全一致.蛋白峰处两管标记C₁₇的比活性分别为5.2和8.9Eu³⁺离子每C₁₇分子,而且C₁₇的标记回收率为64%.标记C₁₇至少在6个月内是稳定的.用铕标记物得到的时间分辨免疫荧光分析的标准曲线具有良好线性和斜率,表明标记物免疫活性良好,而且已用于血清CEA分析.