高脂血症大鼠血小板活化功能分析

目的分析高脂血症大鼠血小板功能的变化。方法24只Wistar大鼠随机分为正常对照组、高脂血症模型组,4周后检测两组大鼠的血脂：总胆固醇（CHO）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）水平。应用流式细胞术检测血小板表面a-颗粒膜糖蛋白（CD62P）的表达、酶联免疫法测定血浆中α颗粒膜蛋白．140（GMP140）浓度。所有数据采用Excel软件建库,SPSS11．5统计软件进行分析。结果正常对照组与高脂血症组CHO、TG、LDL-C、HDL-C,CHO分别是1．846mmol／L VS 13．779mmol／L、0．999mmol／L vs 0．746mmol／L、0．164mmol／L vs 10．680mmol／L、0．583mmol／L vs 0．195mmol／L。CD62P、GMP140水平分别为10．089％ vs 25．169％、10．665ng/mL vs 27．045．g／mL。结论高脂血症能够促使血小板活化。     

Intermediate filament cytoskeleton of the liver in health and disease

Intermediate filaments (IFs) represent the largest cytoskeletal gene family comprising approximately 70 genes expressed in tissue specific manner. In addition to scaffolding function, they form complex signaling platforms and interact with various kinases, adaptor, and apoptotic proteins. IFs are established cytoprotectants and IF variants are associated with >30 human diseases. Furthermore, IF-containing inclusion bodies are characteristic features of several neurodegenerative, muscular, and other disorders. Acidic (type I) and basic keratins (type II) build obligatory type I and type II heteropolymers and are expressed in epithelial cells. Adult hepatocytes contain K8 and K18 as their only cytoplasmic IF pair, whereas cholangiocytes express K7 and K19 in addition. K8/K18-deficient animals exhibit a marked susceptibility to various toxic agents and Fas-induced apoptosis. In humans, K8/K18 variants predispose to development of end-stage liver disease and acute liver failure (ALF). K8/K18 variants also associate with development of liver fibrosis in patients with chronic hepatitis C. Mallory-Denk bodies (MDBs) are protein aggregates consisting of ubiquitinated K8/K18, chaperones and sequestosome1/p62 (p62) as their major constituents. MDBs are found in various liver diseases including alcoholic and non-alcoholic steatohepatitis and can be formed in mice by feeding hepatotoxic substances griseofulvin and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDBs also arise in cell culture after transfection with K8/K18, ubiquitin, and p62. Major factors that determine MDB formation in vivo are the type of stress (with oxidative stress as a major player), the extent of stress-induced protein misfolding and resulting chaperone, proteasome and autophagy overload, keratin 8 excess, transglutaminase activation with transamidation of keratin 8 and p62 upregulation.     

Predicting RNA secondary structures with pseudoknots by MCMC sampling

The most probable secondary structure of an RNA molecule, given the nucleotide sequence, can be computed efficiently if a stochastic context-free grammar (SCFG) is used as the prior distribution of the secondary structure. The structures of some RNA molecules contain so-called pseudoknots. Allowing all possible configurations of pseudoknots is not compatible with context-free grammar models and makes the search for an optimal secondary structure NP-complete. We suggest a probabilistic model for RNA secondary structures with pseudoknots and present a Markov-chain Monte-Carlo Method for sampling RNA structures according to their posterior distribution for a given sequence. We favor Bayesian sampling over optimization methods in this context, because it makes the uncertainty of RNA structure predictions assessable. We demonstrate the benefit of our method in examples with tmRNA and also with simulated data. McQFold, an implementation of our method, is freely available from http://www.cs.uni-frankfurt.de/~metzler/McQFold.     

Identification of a consensus site for TRAF6/p62 polyubiquitination

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an ubiquitin ligase that regulates a diverse array of physiological processes via forming Lys-63 linked polyubiquitin chains. In this study, the lysine selection process for TRAF6/p62 ubiquitination was examined. The protein sequence of two characterized TRAF6/p62 substrates, NRIF and TrkA, revealed a conserved consensus pattern for the ubiquitination site of these two TRAF6 substrates. The consensus pattern established in the verified substrates was common to the other Trk receptor family members, TrkB and TrkC. Interestingly, Lysine 811 in TrkB was selected for ubiquination, and mutation of Lysine 811 diminished the formation of TRAF6/p62 complex that is necessary for effective ubiquination. Moreover, downstream signaling was affected upon binding of BDNF to the mutant TrkB receptor. These findings reveal a possible selection process for targeting a specific lysine residue by a single E3 ligase and underscore the role of the scaffold, p62, in this process.     

沙田柚不同外植体离体培养与植株再生的研究

利用组织培养进行柑桔良种的快速繁殖可以克服常规方法费时的缺点 ,为进一步进行无病原体苗木繁育、诱变育种及遗传转化创造有利条件。目前我国开展此项工作较为广泛 ,已先后在红江橙 [1 ]、柠檬 [2 ]、金柑 [3]、甜橙 [4]及蕉柑 [5]等柑桔类中建立了组织培养的再生体系 ,但在柚类中相关的研究较少。笔者以沙田柚为材料 ,在离体培养条件下 ,成功诱导上下胚轴、根段及子叶的不定芽形成和植株再生。1 　材料与方法1 .1 　植物材料沙田柚种子 ( Citrus grandis Osbeck cv.Shatian Yu)经表面消毒后黑暗培养无菌苗 ,当苗长至 2 0 d左右时 ,将上…     

Integrated proteomics identifies p62-dependent selective autophagy of the supramolecular vault complex

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