Glycogen Synthase Kinase-3β Is Involved in Electroacupuncture Pretreatment via the Cannabinoid CB1 Receptor in Ischemic Stroke

We have previously shown that electroacupuncture (EA) pretreatment produces neuroprotective effects, which were mediated through an endocannabinoid signal transduction mechanism. Herein, we have studied the possible contribution of the phosphorylated form of glycogen synthase kinase-3β (GSK-3β) in EA pretreatment-induced neuroprotection via the cannabinoid CB1 receptor (CB1R). Focal transient cerebral ischemia was induced by middle cerebral artery occlusion in rats. Phosphorylation of GSK-3β at Ser-9 [p-GSK-3β (Ser-9)] was evaluated in the penumbra tissue following reperfusion. Infarct size and neurological score were assessed in the presence of either PI3K inhibitors or a GSK-3β inhibitor 72 h after reperfusion. Cellular apoptosis was evidenced by TUNEL staining and determination of the Bax/Bcl-2 ratio 24 h after reperfusion. The present study showed that EA pretreatment increased p-GSK-3β(Ser-9) 2 h after reperfusion in the ipsilateral penumbra. Augmented phosphorylation of GSK-3β induced similar neuroprotective effects as did EA pretreatment. By contrast, inhibition of PI3K dampened the levels of p-GSK-3β(Ser-9), and reversed not only the neuroprotective effect but also the anti-apoptotic effect following EA pretreatment. Regulation of GSK-3β by EA pretreatment was abolished following treatment with a CB1R antagonist and CB1R knockdown, whereas two CB1R agonists enhanced the phosphorylation of GSK-3β. Therefore we conclude that EA pretreatment protects against cerebral ischemia/reperfusion injury through CB1R-mediated phosphorylation of GSK-3β.     

我国苏云金杆菌研究60年

综述了我国近60年来的苏云金杆菌研究进展,包括资源收集及分类鉴定、Bt新基因的发掘及组学研究、病理学与作用机制、毒力测定、产品标准化、产业化,并就Bt生物农药存在的问题及改善途径进行了探讨。     

AhDMT1, a Fe<Superscript>2+</Superscript> transporter,is involved in improving iron nutrition and N<Subscript>2</Subscript> fixation in nodules of peanut intercropped with maize in calcareous soils

Peanut (Arachis hypogaea L.) is an important legume providing edible proteins and N₂ fixation. However, iron deficiency severely reduces peanut growth in calcareous soils. The maize/peanut intercropping effectively improves iron nutrition and N₂ fixation of peanut under pot and field conditions on calcareous soils. However, little was known of how intercropping regulates iron transporters in peanut. We identified AhDMT1 as a Fe²⁺ transporter which was highly expressed in mature nodules with stronger N₂ fixation capacity. Promoter expression analysis indicated that AhDMT1 was localized in the vascular tissues of both roots and nodules in peanut. Short-term Fe-deficiency temporarily induced an AhDmt1 expression in mature nodules in contrast to roots. However, analysis of the correlation between the complex regulation pattern of AhDmt1 expression and iron nutrition status indicated that sufficient iron supply for long term was a prerequisite for keeping AhDmt1 at a high expression level in both, peanut roots and mature nodules. The AhDmt1 expression in peanut intercropped with maize under 3 years greenhouse experiments was similar to that of peanut supplied with sufficient iron in laboratory experiments. Thus, the positive interspecific effect of intercropping may supply sufficient iron to enhance the expression of AhDmt1 in peanut roots and mature nodules to improve the iron nutrition and N₂ fixation in nodules. This study may also serve as a paradigm in which functionally important genes and their ecological significance in intercropping were characterized using a candidate gene approach.     

Genomic markers on synthetic genomes

Genome synthesis endows scientists the ability of de novo creating genomes absent in nature, by thorough redesigning DNA sequences and introducing numerous custom features. However, the genome synthesis is a labor‐ and time‐consuming work, and thus it is a challenge to verify and quantify the synthetic genome rapidly and precisely. Thus, specific DNA sequences different from native genomic sequences are designed into synthetic genomes during synthesis, namely genomic markers. Genomic markers can be easily detected by PCR reaction, whole‐genome sequencing (WGS) and a variety of methods to identify the synthetic genome from native one. Here, we review types and applications of genomic markers utilized in synthetic genomes, with the hope of providing a guidance for future works.     

草鱼呼肠孤病毒NS31蛋白在昆虫细胞中表达及互作多肽筛选

草鱼呼肠孤病毒(Grasscarpreovirus,GCRV)是引发病毒性草鱼出血病的主要病原.前期研究证实GCRV-S7基因片段编码NS31蛋白是GCRV的非结构蛋白,在病毒感染的中后期表达.为深入开展NS31的具体生物学功能,本研究从GCRV-JX01株病毒基因组中扩增NS31,克隆至pFastBacHTA载体;利用杆状病毒Bac-to-Bac系统成功表达携带his标签的重组蛋白his-NS31;Western-Blot和IFA实验表明重组杆状病毒能够感染昆虫细胞(Sf9)表达NS31,进一步通过his-Ni2+柱纯化NS31,SDS-PAGE鉴定蛋白约为30KD.运用噬菌体展示技术筛选噬菌体12肽库,研究NS31特异性结合多肽.挑取30个克隆进行DNA序列测定,结果表明NS31主要和2种多肽分子相互作用.进一步结合生物信息学分析表明上述多肽与草鱼基因组中6个基因具有同源性,提示其可能是NS31互作蛋白.本研究为深入探索NS31在病毒感染过程中的生物学功能奠定了重要基础.     

红茶菌抗菌蛋白提取与纯化

红茶菌液经过滤、离心、减压浓缩 ,丙酮加盐沉淀 ,Sephadex G-50柱层析后 ,得到两个分子量部分 ,其中小分子量部分有抗菌活性 ,采用尿素— SDS—PAGE测定抗菌蛋白分子量未获成功     

Two crystal forms of helix II of Xenopus laevis 5S rRNA with a cytosine bulge

The crystal structure of r(GCCACCCUG).r(CAGGGUCGGC), helix II of the Xenopus laevis 5S rRNA with a cytosine bulge (underlined), has been determined in two forms at 2.2 A (Form I, space group P4(2)2(1)2, a = b = 57.15 A and c = 43.54 A) and 1.7 A (Form II, space group P4(3)2(1)2, a = b = 32.78 A and c = 102.5 A). The helical regions of the nonamers are found in the standard A-RNA conformations and the two forms have an RMS deviation of 0.75 A. However, the cytosine bulge adopts two significantly different conformations with an RMS deviation of 3.9 A. In Form I, the cytosine bulge forms an intermolecular C+*G.C triple in the major groove of a symmetry-related duplex with intermolecular hydrogen bonds between N4C and O6G, and between protonated N3+C and N7G. In contrast, a minor groove C*G.C triple is formed in Form II with intermolecular hydrogen bonds between O2C and N2G, and between N3C and N3G with a water bridge. A partial major groove opening was observed in Form I structure at the bulge site. Two Ca2+ ions were found in Form I helix whereas there were none in Form II. The structural comparison of these two forms indicates that bulged residues can adopt a variety of conformations with little perturbation to the global helix structure. This suggests that bulged residues could function as flexible latches in bridging double helical motifs and facilitate the folding of large RNA molecules.