Nuclear localization and signalling activity of phosphoinositidase C beta in Swiss 3T3 cells.

The hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdInsP2) is a widespread receptor-coupled signalling system at the plasma membrane of most eukaryotic cells. The existence of an entirely separate nuclear phosphoinositide signalling system is suggested from evidence that purified nuclei synthesize PtdInsP2 and phosphatidylinositol 4-phosphate (PtdInsP) in vitro and that a transient decrease in the mass of these lipids occurs when Swiss 3T3 cells are cultured in the presence of insulin-like growth factor-1 (IGF-1). These IGF-1-dependent changes in inositol lipids coincide with an increase in nuclear diacyglycerol and precede translocation to the nucleus and activation of protein kinase C (refs 5, 6). Circumstantial evidence that links these changes with mitosis comes from the isolation of a 3T3 clone that expresses the type-1 IGF receptor and binds IGF-1 peptide but does not respond mitogenically or show transient mass changes in nuclear inositol lipids. A key question is how IGF-1 initiates the rapid breakdown of PtdInsP and PtdInsP2 in the nucleus. Here we present evidence that nuclei of 3T3 cells contain the beta-isozyme of phosphoinositidase C, whereas the gamma-isozyme is confined to the cytoplasm and that IGF-1 treatment stimulates exclusively the activity of nuclear phosphoinositidase C.     

Dirichlet公式的简化证明及应用

本文给出了Ｄｉｒｉｃｈｌｅｔ公式的一个简化证明，极易掌握。利用这一公式导出了一个含双参数的级数及其和的表达式。适当选取参数，得出了几个新的收敛级数。     

绿豆子叶衰老过程中线粒体膜对几种氨基酸的透性

采用线粒体膨胀技术就不同衰老程度的绿豆子叶线粒体膜对氨基酸的透性进行了测定，结果表明，随着绿豆子叶的衰老，离体线粒体膜在脯氨酸、丝氨酸和甘氨酸等渗溶液中的膨胀率从２ｄ龄至５ｄ龄子叶逐渐下降，５ｄ龄时，线粒体结构与功能已受到明显破坏，文中对膨胀率下降的原因进行了讨论。     

Lagrange方程在非惯性参考系中的表达形式

本文给出了完整定常系统在非惯性参考系的Ｌａｇｒａｎｇｅ方程，并举例说明了该表达式的应用。     

平面弹性连杆机构的KED分析

本文放弃了文献中引用的运动学假设和瞬时结构假定,考虑了刚体运动和弹性变形运动之间的耦合项,分析了梁的横向位移对轴向应变的影响。利用虚位移原理和达明贝尔原理,建立了构件和系统的运动微分方程式。以四杆较接机构为例,进行了KED分析。从所得结果可以看出,本文更好地反映出弹性对机构动态误差的影响。     

DNA fingerprinting transforms the art of cell authentication.

The increasing diversity of new cell cultures is seriously stretching the capabilities of traditional methods of identification. DNA fingerprinting is set to play an important role in increasing confidence in the authenticity of cultures in research and industry.     

Periodic paralysis in quarter horses: a sodium channel mutation disseminated by selective breeding.

We recently reported on a linkage study within a Quarter Horse lineage segregating hyperkalaemic periodic paralysis (HYPP), an autosomal dominant condition showing potassium-induced attacks of skeletal muscle paralysis. HYPP co-segregated with the equine adult skeletal muscle sodium channel alpha subunit gene, the same gene that causes human HYPP. We now describe the Phe to Leu mutation in transmembrane domain IVS3 which courses the horse disease. This represents the first application of molecular genetics to an important horse disease, and the data will provide an opportunity for control or eradication of this condition.     

（NPX2）3（X=F,Cl,Br,I）的几何构型和振动频率的MNDO研究

运用ＭＮＤＯ方法对标题化合物的几何构型和振动频率进行了理论计算，计算出来的结构参数与晶体Ｘ－射线实验数据一致；计算出来的捱劝频率与红外和拉曼光谱基本一致，最后，计算得出目前在实验上尚未报道的（ＮＰＩ２）３的上述两个方面的理论数据。