谷胱甘肽的抗线粒体脂质过氧化作用

谷胱甘肽是细胞内重要的抗氧化损伤物质之一．以NADH诱导的牛心肌线粒体脂质过氧化体系为模型,研究了谷胱甘肽的抗氧化作用．结果表明,一定浓度的谷胱甘肽能够部分抑制该体系中线粒体的脂质过氧化．保护组的丙二醛含量为损伤组72．5％;线粒体的膨胀度较损伤组降低;细胞色素C氧化酶及ATP酶活力分别较损伤组提高了1．5及2．2倍．     

表达甲型肝炎病毒抗原的重组痘苗病毒(VMS11 HAV25)的免疫原性

甲型肝炎(甲肝)病毒基因全部开放读码框架cDNA重组于痘苗病毒天坛株DNA的HindⅢM片段,获得了重组痘苗病毒VMS11HAV25。用10~7PFU或10~8PFU病毒量皮内免疫家兔,能诱生甲肝病毒抗体,其滴度与免疫剂量、免疫次数及间隔有关。组织培养中和试验表明,该抗体具有中和甲肝病毒的能力。VMS11HAV25的免疫效果似优于本实验室已报道的另一株甲肝病毒基因重组于TK区的重组痘苗病毒Re41。     

mTOR drives its own activation via SCF(βTrCP)-dependent degradation of the mTOR inhibitor DEPTOR

The activities of both mTORC1 and mTORC2 are negatively regulated by their endogenous inhibitor, DEPTOR. As such, the abundance of DEPTOR is a critical determinant in the activity status of the mTOR network. DEPTOR stability is governed by the 26S-proteasome through a largely unknown mechanism. Here we describe an mTOR-dependent phosphorylation-driven pathway for DEPTOR destruction via SCF(βTrCP). DEPTOR phosphorylation by mTOR in response to growth signals, and in collaboration with casein kinase I (CKI), generates a phosphodegron that binds βTrCP. Failure to degrade DEPTOR through either degron mutation or βTrCP depletion leads to reduced mTOR activity, reduced S6 kinase activity, and activation of autophagy to reduce cell growth. This work expands the current understanding of mTOR regulation by revealing a positive feedback loop involving mTOR and CKI-dependent turnover of its inhibitor, DEPTOR, suggesting that misregulation of the DEPTOR destruction pathway might contribute to aberrant activation of mTOR in disease.     

Simultaneous modification of three homoeologs of TaEDR1 by genome editing enhances powdery mildew resistance in wheat

Wheat (Triticum aestivum L.) incurs significant yield losses from powdery mildew, a major fungal disease caused by Blumeria graminis f. sp. tritici (Bgt). enhanced disease resistance1 (EDR1) plays a negative role in the defense response against powdery mildew in Arabidopsis thaliana; however, the edr1 mutant does not show constitutively activated defense responses. This makes EDR1 an ideal target for approaches using new genome‐editing tools to improve resistance to powdery mildew. We cloned TaEDR1 from hexaploid wheat and found high similarity among the three homoeologs of EDR1. Knock‐down of TaEDR1 by virus‐induced gene silencing or RNA interference enhanced resistance to powdery mildew, indicating that TaEDR1 negatively regulates powdery mildew resistance in wheat. We used CRISPR/Cas9 technology to generate Taedr1 wheat plants by simultaneous modification of the three homoeologs of wheat EDR1. No off‐target mutations were detected in the Taedr1 mutant plants. The Taedr1 plants were resistant to powdery mildew and did not show mildew‐induced cell death. Our study represents the successful generation of a potentially valuable trait using genome‐editing technology in wheat and provides germplasm for disease resistance breeding.     

毛竹茎秆叶绿体超微结构及其发射荧光光谱特征

为了探讨毛竹（Phyllostachys pubescens）茎秆的光合特性,以1龄和3龄毛竹为材料,观察了茎秆和叶中叶绿体的超微结构,测定了光合色素含量以及发射荧光光谱。结果表明：茎秆中叶绿体发育完整,其类囊体垛叠程度高于叶,并含有淀粉粒。茎秆中叶绿素总含量、类胡萝卜素及Chla／b含量显著低于叶（FI〈O．05）。茎秆发射荧光光谱在735nm处没有明显的主峰,1龄和3龄毛竹茎秆光系统lI与光系统I的半峰宽比值分别比叶降低了7．0％和11．3％（P〈0．05）,峰高比值比叶分别增加了6．5％和18．3％（P〈0．05）。四阶导数光谱在650—800nm波长范围内出现了6个极大值,代表LHCII、CP43、CP47、RCI和ILHCI的发射荧光峰以及PSI和PSII的发射荧光副振峰：其中,茎秆中RCI和LHCI特征发射荧光峰与叶相比有不同程度的红移。表明毛竹茎秆叶绿体通过提高Chlb的相对含量和增加类囊体垛叠以及降低LHCI含量,来适应毛竹茎秆以红光为主的光环境。进而协调激发能在2个光系统间的分配。     

Synthesis and evaluation of 1,2,4-triazolo[1,5-c]pyrimidine derivatives as A2A receptor-selective antagonists

Movement disorders such as Parkinson’s disease and Huntington’s disease are serious life-limiting and debilitating movement disorders. Their onset typically occurs from mid-life to late in life, and effective diagnostic techniques for detecting and following the disease course are lacking. Our goal is to develop receptor imaging agents for positron emission tomography (PET) that selectively target the most relevant subtype of adenosine receptors (AR) that are highly expressed in the striatum, that is, the A_2A AR. To further this goal, we have synthesized and characterized pharmacologically a family of high affinity A_2A AR ligands, based on the known antagonist, SCH 442416 (R = –Me), which have structural variability on the terminus (R = –Et, –i-Pr, –allyl, and others). A O-fluoroethyl analogue suitable for use as a PET tracer had a K_i value of 12.4 nM and was highly selective for the A_2A AR in comparison to the A₁ and A₃ ARs.     

Coronary endothelial dysfunction after cardiomyocyte-specific mineralocorticoid receptor overexpression

The deleterious effects of aldosterone excess demonstrated in cardiovascular diseases might be linked in part to coronary vascular dysfunction. However, whether such vascular dysfunction is a cause or a consequence of the changes occurring in the cardiomyocytes is unclear. Moreover, the possible link between mineralocorticoid receptor (MR)-mediated effects on the cardiomyocyte and the coronary arteries is unknown. Thus we used a mouse model with conditional, cardiomyocyte-specific overexpression of human MR (hMR) and observed the effects on endothelial function in isolated coronary segments. hMR overexpression decreased the nitric oxide (NO)-mediated relaxing responses to acetylcholine in coronary arteries (but not in peripheral arteries), and this was prevented by a 1-mo treatment either with an MR antagonist, vitamin E/vitamin C, or a NADPH oxidase inhibitor. hMR overexpression did not affect coronary endothelial NO synthase content nor its level of phosphorylation on serine 1177, but increased cardiac levels of reactive oxygen species, cardiac NADPH oxidase (NOX) activity, and expression of the NOX subunit gp91phox, which was limited to endothelial cells. Thus an increase in hMR activation, restricted to cardiomyocytes, is sufficient to induce a severe coronary endothelial dysfunction. We suggest a new paracrine mechanism by which cardiomyocytes trigger a NOX-dependent, reactive oxygen species-mediated coronary endothelial dysfunction.     

中国传统大菊叶片形态的数量化定义与分类

中国传统大菊品种叶片形态变异丰富,然而至今仍未对其进行科学的定义和分类,无法有效利用这些形态性状进行品种鉴定和叶形遗传解析。利用数量化分析方法对植物形态进行定义和分类,是植物性状遗传解析的前提。对436个中国传统大菊品种的24个叶形性状进行重新定义及观测,通过相关性分析确定了8个相对独立的性状,用变异系数及主成分分析等...