Role of IKK/NF-κB signaling in extinction of conditioned place aversion memory in rats

The inhibitor κB protein kinase/nuclear factor κB (IKK/NF-κB) signaling pathway is critical for synaptic plasticity. However, the role of IKK/NF-κB in drug withdrawal-associated conditioned place aversion (CPA) memory is unknown. Here, we showed that inhibition of IKK/NF-κB by sulphasalazine (SSZ; 10 mM, i.c.v.) selectively blocked the extinction but not acquisition or expression of morphine-induced CPA in rats. The blockade of CPA extinction induced by SSZ was abolished by sodium butyrate, an inhibitor of histone deacetylase. Thus, the IKK/NF-κB signaling pathway might play a critical role in the extinction of morphine-induced CPA in rats and might be a potential pharmacotherapy target for opiate addiction.     

一种目视激光显微镜

本文介绍一种目视激光显微镜。该装置采用白炽灯和激光做光源。通过调压器衬底亮度可以调整到零。由于激光的高亮度和强相干性,与普通显微镜相比,该显微镜具有景深长,分辨率高,层次丰富的特点。使用该显微镜时能实现镜象的假色彩编码,且镜象具有立体感。文中报导了该显微镜的原理和使用效果。     

Urinary-type plasminogen activator receptor (uPAR) modulates oral cancer cell behavior with alteration in p130cas

Oral cavity cancer is among the most frequently diagnosed cancers worldwide and urinary-type plasminogen activator receptor (uPAR) is clinically associated with more invasive tumors and enhanced lymph node metastasis. We seek to further elucidate the mechanism of by which uPAR promotes cell aggressiveness in the unique context of oral squamous cell carcinoma (OSCC). The contribution of uPAR expression to aggressive cellular behavior of OSCC was examined using in vitro cellular models wherein the expression of uPAR was manipulated and in a human OSCC tissue microarray. Results show altered adhesion, motility, and invasion in cells that overexpress uPAR relative to vector control cells. Distinct alterations of focal adhesion protein expression and phosphorylation, including p130cas and paxillin were observed, suggestive of enhanced focal adhesion turnover. Immunohistochemical analysis of microarrayed human OSCC revealed a significant correlation between uPAR and p130cas expression. The non-receptor protein tyrosine kinase c-Src was responsible for the phosphorylation of p130cas in response to uPAR/α3β1/laminin-5 engagement. Further downstream, the Rho family GTPase Cdc42, but not Rac1, was activated, suggesting a pathway leading to actin reorganization, filopodial protrusion and enhanced motility in uPAR overexpressing oral cancer cells. These data shed light on a molecular mechanism whereby acquisition of uPAR expression may modulate OSCC invasive activity through alteration of focal adhesion dynamics.     

芋侧球茎发生发育的形态学机理

观察了魁芋和多子芋腋芽、侧球茎发生发育的形态学变化规律,分析了主球茎顶芽和不同发育期腋芽中蛋白质的组成。结果表明,魁芋每一叶轮上腋芽数目为１;多子芋为３或３个以上,其中一个体积较大。魁芋侧球茎发育初期伸长的速度大于增粗,首先形成圆柱型,然后顶端膨大形成体积很小的侧球茎。多子芽腋芽伸的同时茎部明显变粗,首先形成圆锥型,然后发育成品种特有的形状。根据发育进程将腋芽发育分成ＡＢ１－ＡＢ９个时期,将主球茎     

Equilibrium unfolding mechanism of chicken muscle triose phosphate isomerase

Triose phosphate isomerase (TIM) was prepared and purified from chicken breast muscle. The equilibrium unfolding of TIM by urea was investigated by following the changes of intrinsic fluorescence and circular dichroism spectroscopy, and the equilibrium thermal unfolding by differential scanning calorimetry (DSC). Results show that the unfolding of TIM in urea is highly cooperative and no folding intermediate was detected in the experimental conditions used. The thermodynamic parameters of TIM during its urea induced unfolding were calculated as DeltaG degrees =3.54 kcal.mol(-1), and m(G) = 0.67 kcal.mol(-1)M(-1), which just reflect the unfolding of dissociated folded monomer to fully unfolded monomer transition, while the dissociation energy of folded dimer to folded monomer is probe silence. DSC results indicate that TIM unfolding follows an irreversible two-state step with a slow aggregation process. The cooperative unfolding ratio, DeltaH(cal)/DeltaH(vH), was measured close to 2, indicating that the two subunits of chicken muscle TIM unfold independently. The van't Hoff enthalpy, DeltaH(vH), was estimated as about 200 kcal.mol(-1). These results support the unfolding mechanism with a folded monomer formation before its tertiary structure and secondary structure unfolding.     

Red重组系统及在微生物基因敲除中的应用

在完成了对各种微生物基因组的测序以后,功能基因学的研究变得尤为重要。研究基因功能最直接的方法便是将待研究的基因失活。最初构建基因突变体是采用大肠杆菌的RecA系统,但是RecA重组系统操作复杂,重组效率低。最近建立了Red重组系统,该系统由3个蛋白组成：α蛋白(即λ核酸外切酶),β蛋白,Gam蛋白。应用Red系统进行基因敲除,可以直接利用线性打靶DNA,两侧同源臂长度在35~60 bp即可发生同源重组,且重组效率高。 Abstract:Since many DNA-sequencing projects of varied microorganisms have been completed,studies on their functional genomics become more important.Inactivation of an interesting gene is a direct method to characterize its function.Though the Esherichia coli RecA recombination system can be used to produce gene mutants,it needs a complex manipulation process.Furthermore,its efficiency is very low.Recently a Red recombination system was developed.This recombination system consists of three proteins:α protein（λ exonuclease）,β protein and Gam protein.In this system,the linear targeting DNA which contains a selectable marker flanked with a homologous region as short as only 35~60 bp can be directly targeted for gene knock-out with a higher efficiency.     

Solution structure of human SUMO-3 C47S and its binding surface for Ubc9

Small ubiquitin-related modifier SUMO-3 is a member of a growing family of ubiquitin-like proteins (Ubls). So far, four isoforms of SUMO have been identified in humans. It is generally known that SUMO modification regulates protein localization and activity. Previous structure and function studies have been mainly focused on SUMO-1. The sequence of SUMO-3 is 46% identical with that of SUMO-1; nevertheless, functional heterogeneity has been found between the two homologues. Here we report the solution structure of SUMO-3 C47S (residues 14-92) featuring the beta-beta-alpha-beta-beta-alpha-beta ubiquitin fold. Structural comparison shows that SUMO-3 C47S resembles ubiquitin more than SUMO-1. On the helix-sheet interface, a strong hydrophobic interaction contributes to formation of the globular and compact fold. A Gly-Gly motif at the C-terminal tail, extending away from the core structure, is accessible to enzymes and substrates. In vivo, SUMO modification proceeds via a multistep pathway, and Ubc9 plays an indispensable role as the SUMO conjugating enzyme (E2) in this process. To develop a better understanding of SUMO-3 conjugation, the Ubc9 binding surface on SUMO-3 C47S has been detected by chemical shift perturbation using NMR spectroscopy. The binding site mainly resides on the hydrophilic side of the beta-sheet. Negatively charged and hydrophobic residues of this region are highly or moderately conserved among SUMO family members. Notably, the negatively charged surface of SUMO-3 C47S is highly complementary in its electrostatic potentials and hydrophobicity to the positively charged surface of Ubc9. This work indicates dissimilarities between SUMO-3 and SUMO-1 in tertiary structure and provides insight into the specific interactions of SUMO-3 with its modifying enzyme.     

Template-based modeling and ab-initio docking using CoDock in CAPRI

Integration of template-based modeling, global sampling and precise scoring is crucial for the development of molecular docking programs with improved accuracy. We combined template-based modeling and ab-initio docking protocol as hybrid docking strategy called CoDock for the docking and scoring experiments of the seventh CAPRI edition. For CAPRI rounds 38-45, we obtained acceptable or better models in the top 10 submissions for eight out of the 16 evaluated targets as predictors, nine out of the 16 targets as scorers. Especially, we submitted acceptable models for all of the evaluated protein-oligosaccharide targets. For the CASP13-CAPRI experiment (round 46), we obtained acceptable or better models in the top 5 submissions for 10 out of the 20 evaluated targets as predictors, 11 out of the 20 targets as scorers. The failed cases for our group were mainly the difficult targets and the protein-peptide systems in CAPRI and CASP13-CAPRI experiments. In summary, this CAPRI edition showed that our hybrid docking strategy can be efficiently adapted to the increasing variety of challenges in the field of molecular interactions.