Archaeal acylamino acid releasing enzyme/lipase:Crystallization and preliminary crystallographic analysis in a new crystal form

A primitive orthorhombic crystal form of acylamino acid releasing enzyme‘lipase(APE1547)from hyperthermophilic archaeon Aeropyrum pernix strain K1 has been obtained at 291K.The diffraction pattern of the crystal extends to 0.27nm resolution at 100K using Cu Kαradiation.The crystal belongs to the space group P212121 with unit cell dimensions of b=6.399,b=10.439and c=16.953nm.The presence of two molecules per asymmetric unit gives a crystal volume per protein mass(Vm)of 0.0022nm^3 Da^-1 and a solvent content of 43% by volume.A full set of X-ray diffraction data were collected to 0.3nm from the native crystal.     

Measurements of leucocyte membrane elasticity based on the optical tweezers

A 1-μm in diameter polystyrene bead coated with lectin is trapped by optical tweezers whics is formed by a focused laser beam (740nm).A leucocyte adhered to the bottom of sample cell is chosen to close to the trapped bead.When their stable combination is confirmed,the leucocyte is displaced by moving the sample stage.A“tether”is then formed between the trapped bead and the membrane.The force acting on the tether is measured by a detector equipped on the optical tweezers system.The deformation of the membrane is diverse in different contact conditions.When the contact area is small,the tether is very thin and the force on it is 7.4pN(10^-12N),while the tether is much thicker under a larger contact area and its corresponding force is about 14pN.It is presumed that the latter is related to the deformation of cytoskeleton.     

铂(II)与胺类配合物的合成、晶体结构和抗肿瘤活性研究

研究铂(II)与三种胺类配合物的合成、晶体结构和体外抗肿瘤活性,化合物1的X-射线单晶结构分析表明:这是一个很少见的具有四方锥几何构型的铂(II)配合物,顺式平面四方形配位的铂的轴向上有第5个配位原子。其抗肿瘤活性实验显示3个配合物对几种研究的癌细胞都有较强的抑制作用。     

Some Properties of Fractals Generated by Linear Cellular Automata

Fractals and cellular automata are both significant areas of research in nonlinear analysis. This paper studies a class of fractals generated by cellular automata. The patterns produced by cellular automata give a special sequence of sets in Euclidean space. The corresponding limit set is shown to be a fractal and the dimension is independent of the choice of the finite initial seed. As opposed to previous works, the fractals here do not depend on the time parameter.     

Effects of hyaluronic acid－chitosan－gelatin complex on the apoptosis and cell cycle of L929 cells

With the development in the field of tissue engineering, the interaction between biomaterials and cells has been deeply studied. Viewing the cells seeded on the surface of materials as an organic whole, cell cycle and apoptosis are analyzed to deepen the study of cell compatibility on biomaterials, while cell proliferation and differentiation are studied at the same time. In this paper, hyaluronic acid is incorporated into the chitosan-gelatin system. Propidium iodide (PI) was used in cell cycle analysis and the double-staining of cells with annexin-V and PI was applied in cell apoptosis analysis. The results show that incorporated hyaluronic acid shortens the adaptation period of cells on the material surface, and then cells enter the normal cell cycle quickly. In addition, added hyaluronic acid inhibits cell apoptosis triggered by the membranes. Therefore, hyaluronic acid improves the cell compatibility of chitosan-gelatin system and benefits the design of biomimetic materials.     

Building of hFⅨ transgenic mice by spermatogenic cells

Human FⅨ expression vector pCMVⅨ was packaged by effectene^TM reagent and injected into mice seminiferous tubules with glass pipettes.The expressional frame of pCMVⅨ was examined by PCR and Southern blotting among 41 progenies.There were 2(4%) mice being integrated with hFⅨ gene into chromosomes.4.6ng/mL of hFⅨ protein was expressed in plasma of one mouse,which was tested by ELISA.We demonstrated that building of transgenic animals by spermatogonial stem cells is an efficient method.Meanwhile,it has also been proved to be an alternative choice for mammary gland bioreactor.     

彗星电泳检测细胞DNA损伤应用新进展

彗星电泳是近年发展起来的一种测定单个细胞DNA损伤的方法 ,因其操作简单、快速及灵敏等特点 ,应用范围十分广泛 .着重介绍了这一技术的发展、图形分析及应用进展     

口服转胸腺素α1基因聚球藻对小鼠T细胞亚群作用的研究

为探讨口服后转胸腺α1(Tα1)基因聚球藻对T细胞亚群的作用,将小鼠随机分为空白对照组、野生藻组、转化藻(小剂量、中剂量和大剂量)组和日达仙组,用灌服的方式,给予空白对照组20mL·kg~(-1)的生理盐水,野生藻组0.4g·kg~(-1)的野生聚球藻;转化藻小、中、大剂量组,分别0.2g·kg~(-1)、0.4g·kg~(-1)和0.6g·kg~(-1)的转Tα1基因聚球藻;日达仙组则肌注给予3.2mg·kg~(-1)的胸腺素α1(日达仙)。结果表明转Tα1基因藻口服后可显著提高CD3亚群水平,显著提高CD4亚群水平,明显提高CD4/CD8的比值。提示转Tα1基因聚球藻具有增强机体免疫功能的作用。     

华美外滑刃线虫和巨球外真滑刃线虫中国新记录

作者从2001年7月至2002年7月在福建省厦门、南平、龙岩等地共采集松树木质部样品221份，分离发现80份(36％)样品中含有外滑刃科线虫，60份(27％)样品中含有华美外滑刃线虫Ektaphelenchoides compsi Baujard,1984，华美外滑刃线虫厦门虫口与法国虫口相似，但在体长和交合刺长度上略有区别；20份(9％)样品中含有巨球外真滑刃线虫Ektaphelenchus macrobulbosus(Ruhm，1956)Goodey，1960，Baujard，1984，巨球外真滑刃线虫厦门虫口与德国及法国虫口相似．但在体长和口针长度上有所不同．其中华美外滑刃线虫和巨球外真滑刃线虫为中国新记录种．