Receptor communication within the lymphocyte plasma membrane: a role for the thrombospondin family of matricellular proteins

Lymphocytes, the principal cells of the immune system, carry out immune surveillance throughout the body by their unique capacity to constantly reposition themselves between a free-floating vascular state and a tissue state characterized by migration and frequent adhesive interactions with endothelial cells and components of the extracellular matrix. Therefore, mechanisms co-ordinating adhesion and migration with signals delivered through antigen recognition probably play a pivotal role for the regulation of lymphocyte behaviour and function. Endogenous thrombospondin-1 (TSP-1) seems to be the hub in such a mechanism for autocrine regulation of T cell adhesion and migration. TSP-1 functions as a mediator of cis interaction of vital receptors within the T lymphocyte plasma membrane, including integrins, low density lipoprotein receptor-related protein, calreticulin and integrin-associated protein. Received 1 June 2006; received after revision 28 June 2006; accepted 11 October 2006     

Genetic studies of diseases

Genomic alterations lead to cancer complexity and form a major hurdle for comprehensive understanding of the molecular mechanisms underlying oncogenesis. In this review, we describe recent advances in studying cancer-associated genes from a systems biology point of view. The integration of known cancer genes onto protein and signaling networks reveals the characteristics of cancer genes within networks. This approach shows that cancer genes often function as network hub proteins which are involved in many cellular processes and form focal nodes in information exchange between many signaling pathways. Literature mining allows constructing gene-gene networks, in which new cancer genes can be identified. The gene expression profiles of cancer cells are used for reconstructing gene regulatory networks. By doing so, genes which are involved in the regulation of cancer progression can be picked up from these networks, after which their functions can be further confirmed in the laboratory.     

tRNase Z: the end is not in sight

Although the enzyme tRNase Z has only recently been isolated, a plethora of data has already been acquired concerning the enzyme. tRNase Z is the endonuclease that catalyzes the removal of the tRNA 3′ trailer, yielding the mature tRNA 3′ end ready for CCA addition and aminoacylation. Another substrate cleaved by tRNase Z is the small chromogenic phosphodiester bis(p-nitrophenyl)phosphate (bpNPP), which is the smallest tRNase Z substrate known so far. Hitherto the biological function as tRNA 3′-end processing enzyme has been shown only in one prokaryotic and one eukaryotic organism, respectively. This review summarizes the present information concerning the two tRNase Z substrates pre-tRNA and bpNPP, as well as the metal requirements of tRNase Z enzymes. Received 29 March 2007; received after revision 15 May 2007; accepted 21 May 2007     

Computational protein function prediction: Are we making progress?

The computational prediction of gene and protein function is rapidly gaining ground as a central undertaking in computational biology. Making sense of the flood of genomic data requires fast and reliable annotation. Many ingenious algorithms have been devised to infer a protein's function from its amino acid sequence, 3D structure and chromosomal location of the encoding genes. However, there are significant challenges in assessing how well these programs perform. In this article we explore those challenges and review our own attempt at assessing the performance of those programs. We conclude that the task is far from complete and that a critical assessment of the performance of function prediction programs is necessary to make true progress in computational function prediction.     

聚合氯化铝组合芽孢杆菌发酵液法对链状裸甲藻孢囊种源萌发调控研究

对比不同浓度梯度的聚合氯化铝(poly aluminium chloride,以下简称"PAC")和不同发酵时间、不同投加量的Ba3芽孢杆菌(Bacillus)发酵液及两者组合法对链状裸甲藻(Gymnodinium catenatum)的除藻效果,用最佳投加量进行了沉积物种源萌发调控实验,探究了PAC组合菌发酵液方法对...     

页岩结构完整性评价的热-流体-变形耦合理论与方法

该文应用连续介质力学理论建立了与蒸汽注入过程相关的热-流-变形耦合问题的基本数学模型;应用全隐式顺序Galerkin有限元数值解方案,对注蒸汽井的热-流体-变形耦合过程进行了数值模拟。结果表明,由于低渗透页岩地层流体高温膨胀导致的超高孔隙压力,有可能产生拉张应力,严重时会导致地层破裂。     

进化论的故乡

加拉帕戈斯群岛位于东太平洋,距离南美大陆约1000千米。群岛由大大小小19座岛屿和无数的岸礁组成,这些岛屿都是远古时代由海底火山喷发出的岩浆堆积而成的火山岛。几百万年以来,许多动植物被洋流和季风由美洲、加勒比海和南极送往这座群岛,与世隔绝地在不同的岛屿上各自进化。19世纪30年代,达尔文曾上岛研究这些独特的动植物,这对他后来提出进化论起到了重大影响。因此,加拉帕戈斯群岛被誉为“进化论的故乡”。进化论的故乡~~     

哈特曼装置上粉尘浓度的测量

粉尘浓度和湍流速度对粉尘爆炸猛烈程度和粉尘云最小着火能的测试有很大影响.针对1.2 L哈特曼装置上的粉尘浓度进行了测量研究,并对测量数据进行了分析讨论,得到了1.2 L哈特曼管上不同位置高度的粉尘浓度随时间的变化曲线.粉尘浓度随哈特曼管高度位置分布很不均匀.对于哈特曼管电极位置高度,当点火延迟时间170 ms、计算浓度为500 g/m3时,其粉尘测量浓度近似等于计算浓度;当计算浓度低于500 g/m3时,其测量浓度高于计算浓度.当计算浓度大于500 g/m3时,测量浓度低于计算浓度.哈特曼管上粉尘浓度随高度分布的获得,为最小着火能在不同装置上的测试比较提供了数据,为粉尘爆炸数学模型的检验提供了...     

Displacement Discontinuity Method in 3D Problems of Fracture Mechanics

The present paper suggests a modification of boundary elements numerical method, which uses displacement discontinuity method in 3D space. The current method can effectively decrease the computational elements number in 3D space because final elements are placed only on the surface of a fracture simulating the discontinuity of elastic medium. Thus the dimension of the problem is decreased. The new fundamental solutions were developed based on double layer potentials. The method proved to be effective for hydraulic fractures modeling and their interaction with natural faults in host rock formations.