Cross‐talk between EGF and BMP9 signalling pathways regulates the osteogenic differentiation of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are multipotent progenitors, which give rise to several lineages, including bone, cartilage and fat. Epidermal growth factor (EGF) stimulates cell growth, proliferation and differentiation. EGF acts by binding with high affinity to epidermal growth factor receptor (EGFR) on the cell surface and stimulating the intrinsic protein tyrosine kinase activity of its receptor, which initiates a signal transduction cascade causing a variety of biochemical changes within the cell and regulating cell proliferation and differentiation. We have identified BMP9 as one of the most osteogenic BMPs in MSCs. In this study, we investigate if EGF signalling cross‐talks with BMP9 and regulates BMP9‐induced osteogenic differentiation. We find that EGF potentiates BMP9‐induced early and late osteogenic markers of MSCs in vitro, which can be effectively blunted by EGFR inhibitors Gefitinib and Erlotinib or receptor tyrosine kinase inhibitors AG‐1478 and AG‐494 in a dose‐ and time‐dependent manner. Furthermore, EGF significantly augments BMP9‐induced bone formation in the cultured mouse foetal limb explants. In vivo stem cell implantation experiment reveals that exogenous expression of EGF in MSCs can effectively potentiate BMP9‐induced ectopic bone formation, yielding larger and more mature bone masses. Interestingly, we find that, while EGF can induce BMP9 expression in MSCs, EGFR expression is directly up‐regulated by BMP9 through Smad1/5/8 signalling pathway. Thus, the cross‐talk between EGF and BMP9 signalling pathways in MSCs may underline their important roles in regulating osteogenic differentiation. Harnessing the synergy between BMP9 and EGF should be beneficial for enhancing osteogenesis in regenerative medicine.     

马尾松和杉木树干韧皮部水溶性糖 δ13C值对气象因子的响应

通过测定亚热带马尾松和杉木树干韧皮部水溶性糖δ¹³C值的连日变化,及其对天气变化过程的响应,研究δ¹³C值对短期天气变化动态的响应特征。结果显示,春季马尾松和杉木树干韧皮部水溶性糖δ¹³C日均值分别介于-26.81‰到-26.49‰之间,以及-29.26‰到-27.47‰之间,平均值分别为(-26.58±0.12)‰和(-28.67±0.65)‰。进一步分析表明,马尾松树干韧皮部水溶性糖δ¹³C值与取样之前第4天的太阳辐射、水气压亏缺、相对湿度和空气温度显著相关(P≤0.05),杉木树干韧皮部水溶性糖δ¹³C值取样之前第3天的太阳辐射、水气压亏缺和相对湿度显著相关(P≤0.05),但与空气温度的相关性不显著(P≤0.05)。在所测定的环境因子中,太阳辐射是影响马尾松和杉木树干韧皮部水溶性糖δ¹³C值的首要因素。当天降水事件可能导致马尾松和杉木树干韧皮部水溶性糖δ¹³C值连日变化出现异常波动。马尾松和杉木韧皮部水溶性糖δ¹³C值可以敏感记录短期天气变化动态。     

禽传染性支气管炎病毒Nsp2蛋白与宿主蛋白eIF2α的互作鉴定

Nsp2蛋白是冠状病毒的非结构蛋白,在病毒早期感染中具有重要作用。【目的】为初步筛选可能与禽传染性支气管炎病毒(avian infectious bronchitis virus,IBV) Nsp2蛋白互作的宿主蛋白,鉴定Nsp2蛋白与真核翻译起始因子2α亚基(eIF2α)的相互作用。【方法】以pCAGGs-Flag-Nsp2和pCAGGs-Flag载体转染后的鸡胚肾(CEK)细胞为研究对象,利用免疫共沉淀(Co-IP)和液相色谱-串联质谱(LC-MS/MS)技术筛选出可能与IBVNsp2蛋白发生互作的宿主蛋白eIF2α,通过免疫共沉淀和间接免疫荧光试验进一步验证二者相互作用。【结果】经免疫共沉淀与质谱分析后筛选到97个可能与Nsp2蛋白互作的宿主蛋白,其中宿主抗病毒反应的关键蛋白eIF2α与Nsp2蛋白的相互作用通过免疫共沉淀和间接免疫荧光试验,表明二者存在直接互作关系,并共定位于细胞质中;此外,Nsp2蛋白表达和IBV感染都能显著提高宿主内源性eIF2α的转录水平。【结论】利用免疫共沉淀联合质谱技术筛选到CEK细胞中存在的97种可能与IBV Nsp2互作的候选蛋白,利用免疫共沉淀与...     

黄花倒水莲花中黄酮苷类成分的分离、鉴定及抗氧化活性研究

该研究采用硅胶、Sephadex LH-20柱色谱和HPLC进行分离纯化,并结合1D-NMR波谱数据和文献比对,研究了黄花倒水莲花中黄酮类成分及抗氧化活性。结果表明：（1）从黄花倒水莲花95%乙醇提取物的乙酸乙酯部位中分离鉴定出6个黄酮苷类化合物,即紫云英苷（1）、槲皮素-3-O-β-D-葡萄糖苷（2）、槲皮素-3-O-β-吡喃木糖苷（3）、槲皮素-3-O-α-L-吡喃阿拉伯糖苷（4）、异鼠李素-3-O-β-葡萄糖苷（5）、芦丁（6）,其中化合物1-6均为首次从该植物中分离得到。（2）分别采用DPPH·自由基清除法及FRAP法对花的不同极性部位和所获得化合物进行总抗氧化能力评价,结果显示化合物1-6均表现出较好的抗氧化作用,其中化合物4的总抗氧化能力达到（4.533±0.13）mmol·g^-1(Vc为5.951±0.25 mmol·g^-1)。该研究结果不仅丰富了黄花倒水莲花的物质基础,而且为其今后的综合开发利用提供了科学依据。     

Cloning,Expression and Characterization of the Human <Emphasis Type="BoldItalic">NOB1</Emphasis> gene

The yeast Nob1p (Nin one binding protein) gene is required for proteasome function and RNA metabolism. We report here the cloning and characterization of the human orthologue NOB1 gene and its products. The human NOB1 gene is composed of nine exons and eight introns and is localized on human chromosome 16q22.1. The NOB1 cDNA is 1749 bp long and contains a putative open reading frame of 1239 bp. The predicted NOB1 protein comprises a PIN (PilT amino terminus) domain and a zinc ribbon domain. Western blot analysis showed that the molecular weight of NOB1 is about 50 KDa. RT-PCR analysis of mRNA from human adult tissues showed that NOB1 is expressed mainly in liver, lung and spleen. Expression of NOB1 in mammalian culture cells indicated that the NOB1 protein is mainly localized in the nucleus. Our data provides important information for further study of the function of the NOB1 gene and its products.     

Synthesis, characterization and biological activity of triorganotin 2-phenyl-1,2,3-triazole-4-carboxylates

The triorganotin 2-phenyl-1,2,3-triazole-4-carboxylates, 2-PhC2N3CO2SnR3 (R=C6H5, 1; c-C6H11, 2; C6H5C(CH3)2CH2, 3), have been prepared and characterized by means of elemental analysis, IR and NMR (1H, 13C and 119Sn) spectroscopy. The crystal structures of 1 and 3 have been determined. Compound 1 is polymeric in nature with a trigonal bipyramidal configuration, and compound 3 shows a tetrahedral geometry. Bioassay results have shown that these compounds have good antibacterial and antitumor activity. The activity against three human tumor cell lines (HeLa, CoLo205 and MCF-7) decreased in the order 1>2>3.     

贺兰山10种不同植物的旱生结构研究

对贺兰山10种不同生活型植物的形态解剖研究表明,长期生长在干旱贫瘠环境中植物,均形成适应生境的一些特殊形态结构．叶器官主要表现在：（1）叶表面积与体积之比缩小,表面覆有厚的角质膜,并被有表皮毛,气孔下陷,具孔下室;（2）栅栏薄壁组织细胞明显增多,海绵薄壁组织细胞减少．有叶肉不分化叶、等而叶和异而叶3种结构形式;（3）叶内贮水组织和机械组织增强。轴器官主要表现在：（1）根普遍形成周皮,且木栓层细胞层数增多;（2）机械组织非常发达,在周皮、皮层和韧皮部中有许多厚壁细胞分布。维管组织中的木薄壁细胞的细胞壁也明显木质化加厚;（3）有些植物的根具有异常维管组织。另外,这些植物根、茎、叶中均有粘液细胞和含晶细胞分布。这些结构具有重要的适应干旱生境的意义。     

Cloning and characterization of the CDZFP gene which encodes a putative zinc finger protein.

We report here the cloning and characterization of a novel human cytoplasm-distribution zinc finger protein (CDZFP) gene, isolated from human ovary cDNA library, and mapped to 4p12 by searching the UCSC genomic database. The CDZFP cDNA is 1793 base pairs in length and contains an open reading frame (ORF) encoding 236 amino acids. The CDZFP gene consists of 7 exons and encodes a putative zinc finger protein with a transmembrane region and two zinc finger motifs. Subcellular localization demonstrated that CDZFP protein was located in the cytoplasm when overexpressed in Hela cells and northern blot analysis revealed that CDZFP was ubiquitously expressed in 16 human tissues.     

Measurement of protein size in concentrated solutions by small angle X‐ray scattering

By simulations on the distance distribution function (DDF) derived from small angle X‐ray scattering (SAXS) theoretical data of a dense monodisperse system, we found a quantitative mathematical correlation between the apparent size of a spherically symmetric (or nearly spherically symmetric) homogenous particle and the concentration of the solution. SAXS experiments on protein solutions of human hemoglobin and horse myoglobin validated the correlation. This gives a new method to determine, from the SAXS DDF, the size of spherically symmetric (or nearly spherically symmetric) particles of a dense monodisperse system, specifically for protein solutions with interference effects.     

Structure of a benzylidene derivative of 9(10H)-anthracenone in complex with tubulin provides a rationale for drug design

Microtubules are composed of αβ-tubulin heterodimers and have been treated as highly attractive targets for antitumor drugs. A broad range of agents bind to tubulin and interfere with microtubule assembly, including colchicine binding site inhibitors (CBSIs). Tubulin Polymerization Inhibitor I (TPI1), a benzylidene derivative of 9(10H)-anthracenone, is a CBSI that inhibits the assembly of microtubules. However, for a long time, the design and development of anthracenone family drugs have been hindered by the lack of structural information of the tubulin-agent complex. Here we report a 2.3 Å crystal structure of tubulin complexed with TPI1, the first structure of anthracenone family agents. This complex structure reveals the interactions between TPI1 and tubulin, and thus provides insights into the development of new anthracenone derivatives targeting the colchicine binding site.