Impact of cranberry juice on initial adhesion of the EPS producing bacterium Burkholderia cepacia

The impact of cranberry juice was investigated with respect to the initial adhesion of three isogenic strains of the bacterium Burkholderia cepacia with different extracellular polymeric substance (EPS) producing capacities, viz. a wild-type cepacian EPS producer PC184 and its mutant strains PC184rml with reduced EPS production and PC184bceK with a deficiency in EPS production. Adhesion experiments conducted in a parallel-plate flow chamber demonstrated that, in the absence of cranberry juice, strain PC184 had a significantly higher adhesive capacity compared to the mutant strains. In the presence of cranberry juice, the adhesive capacity of the EPS-producing strain PC184 was largely reduced, while cranberry juice had little impact on the adhesion behavior of either mutant strain. Thermodynamic modeling supported the results from adhesion experiments. Surface force apparatus (SFA) and scanning electron microscope (SEM) studies demonstrated a strong association between cranberry juice components and bacterial EPS. It was concluded that cranberry juice components could impact bacterial initial adhesion by adhering to the EPS and impairing the adhesive capacity of the cells, which provides an insight into the development of novel treatment strategies to block the biofilm formation associated with bacterial infection.     

Danshen-Gegen decoction protects against hypoxia/reoxygenation-induced apoptosis by inhibiting mitochondrial permeability transition via the redox-sensitive ERK/Nrf2 and PKC?/mKATP pathways in H9c2 cardiomyocytes

Danshen-Gegen (DG) Decoction, an herbal formulation containing Radix Salviae miltiorrhizae and Radix Puerariae lobatae, has been used for the treatment of coronary artery disease in Chinese medicine. In the present study, the involvement of ERK- and PKC?-mediated pathways in the cytoprotection against apoptosis afforded by DG pretreatment was investigated in H9c2 cardiomyocytes. Pretreatment with a methanol extract of aqueous DG decoction protected against hypoxia/reoxygenation-induced apoptosis in H9c2 cardiomyocytes. The cytoprotection was associated the enhancement of cellular reduced glutathione and a reduced sensitivity to Ca²⁺-induced mitochondrial permeability transition. DG extract increased the production of cytochrome P-450 (CYP)-dependent reactive oxygen species (ROS) in H9c2 cardiomyocytes, which was accompanied by the concomitant activation of ERK1/2 and PKC?. The DG-induced ERK1/2 activation was followed by the translocation of Nrf2 from the cytosol to the mitochondria accompanied by an increase in the expression of glutathione-related antioxidant proteins. In addition, the increased expression of hemeoxygenase-1 was associated with the activation of Akt and BAD, indicative of anti-apoptotic activity. In conclusion, DG treatment activated both ERK/Nrf2 and PKC? pathways, presumably by ROS arising from CYP-catalyzed processes, with resultant inhibition of hypoxia/reoxygenation-induced apoptosis immediately after DG treatment or even after an extended time interval following DG treatment.     

Novel Polypyridyl chelators deplete cellular zinc and destabilize the X-linked inhibitor of apoptosis protein (XIAP) prior to induction of apoptosis in human prostate and breast cancer cells

X-linked inhibitor of apoptosis protein (XIAP), inhibits the initiation and execution phases of the apoptotic pathway. XIAP is the most potent member of the inhibitor of apoptosis protein (IAP) family of the endogenous caspase inhibitors. Therefore, targeting XIAP may be a promising strategy for the treatment of apoptosis-resistant malignancies. In this study, we systematically studied the relationships of chemical structures of several novel ligands to their zinc (Zn)-binding ability, molecular target XIAP, and tumor cell death-inducing activity. We show that treatment of PC-3 prostate cancer and MDA-MB-231 breast cancer cells with these membrane-permeable Zn-chelators with different Zn affinities results in varying degrees of XIAP depletion. Following decreased level of XIAP expression, we also show apoptosis-related caspase activation and cellular morphological changes upon treatment with strong Zn-chelators N4Py and BnTPEN. Addition of Zn has a full protective effect on the cells treated with these chelators, while iron (Fe) addition has only partial protection that, however, can be further increased to a comparable level of protection as Zn by inhibition of ROS generation, indicating that cell death effects mediated by Fe- but not Zn-complexes involve redox cycling. These findings suggest that strong Zn-chelating agents may be useful in the treatment of apoptosis-resistant human cancers.     

Crystal structure of agkisacucetin, a Gpib-binding snake C-type lectin that inhibits platelet adhesion and aggregation

Agkisacucetin is a snake C‐type lectin isolated from the venom of Agkistrodon acutus (A. acutus). It binds specifically to the platelet glycoprotein (GP) Ib and prevents the von Willebrand factor (VWF) accessing it. We determined the crystal structure of agkisacucetin to 1.9Å resolution. The structure of agkisacucetin has an (αβ) fold similar to another GPIb‐binding protein, flavocetin‐A, but lacks the C‐terminal cysteine in the β‐subunit, does not form (βα)₄ tetramers, and does not cluster GPIbs, like flavocetin‐A. Proteins 2012;. © 2012 Wiley Periodicals, Inc.     

Ectopic overexpression of swine PPARγ2 upregulated adipocyte genes expression and triacylglycerol in skeletal muscle of mice

Peroxisome proliferator-activated receptor ??2 (PPAR??2) is a key regulator of adipocyte differentiation, fatty acid uptake and storage in mammals. The primary goal of the present study was to investigate the consequences of PPAR??2 overexpression in the muscle. A swine muscle creatine kinase promoter was used to drive swine PPAR??2 (sPPAR??2) overexpression in the muscle of a transgenic mice model. The results showed that the mRNA of multiple adipocyte genes was increased in the skeletal muscle, as evidenced by the up-regulation of fatty acid synthase (2.11-fold, P?<?0.05), lipoprotein lipase (2.08-fold, P?<?0.01), fatty acid-binding protein 4 (14.30-fold, P?<?0.01), and CD36 antigen (5.50-fold, P?<?0.01). Meanwhile, skeletal muscle triacylglycerol was increased (P?<?0.01) and the fatty acid profile of muscle fat was changed in that more polyunsaturated fats acid were augmented. The present study may further serve to develop transgenic pigs with higher intramuscular fat content and improved pork quality.     

核呼吸因子的研究进展

核呼吸因子（nuclear respiratory factors,NRFs）包括NRF-1和NRF-2,属于转录激活因子,在调控核基因编码和线粒体基因编码的呼吸链亚基表达中发挥着直接或间接的作用。除此之外,核呼吸因子还具有调控线粒体运输蛋白基因表达和神经元相关因子合成的作用。就NRF-1和NRF-2的分子生物学结构、生物学功能和调控等三个方面进行综述。     

整合素α3、α6在CD151促进HepG2细胞增殖、侵袭中的作用

目的观察CD151转染HepG2细胞后对细胞增殖,侵袭的影响及其与整合素的关系。方法用脂质体转染试剂,将质粒CD151及其突变体CD151-AAA转染HepG2细胞,观察转染后细胞增殖,侵袭的变化;免疫共沉淀法检测整合素的表达情况。结果 CD151-AAA突变体较CD151促细胞增殖力低,其侵袭力未见增强,且其免疫共沉淀未能检测到整合素的表达。结论 CD151促进HepG2细胞增殖,侵袭有赖于CD151-整合素α3/α6复合体的形成。     

北京市河流滨岸带植被调查

采用样地样方调查法,通过Margalef指数、Shannon-weiner指数和Pielou指数综合分析了北京市3条主要河流(潮白河、拒马河、清水河)的滨岸带植被物种丰富度、多样性及均匀度。结果表明:在11个样地中共记录植物74科248种,其中蕨类植物3科7种,双子叶植物56科166种,单子叶植物15科75种。清水河滨岸带的植物Mar-galef指数、Shannon-weiner指数和Pielou指数均高于潮白河与拒马河,植被状况保持较好。     

果蝇心脏发育标记基因Kruppel的多克隆抗体制备

Kruppel在果蝇发育过程中起着重要的调控作用。为了进一步研究Kruppel的功能,需要制备Kruppel蛋白及其抗体.对已有的Kruppel序列进行分析,选取适当区域进行引物设计,从果蝇心脏cDNA文库中PCR扩增得到Kruppel部分编码区序列,并其连接到pET-28a载体上。将重组质粒（pET-28a-Kruppel）转化rosetta受体菌,通过IPTG（Isopropylβ-D-thiogalactoside）诱导表达融合蛋白,用镍柱进行亲和纯化。将纯化得到的融合蛋白免疫新西兰大白兔制备多克隆抗体,并用Western blot检测抗体的效价。