Enhancement of the antitumor effect of illudin S by including it into liposomes.

Entrapping illudin S in liposome markedly enhanced life prolonging effect in ddN mice bearing Ehrlich ascites tumors, presumably by decreasing the side effects.     

Enhancement of the antitumor effect of illudin S by including it into liposomes

Summary Entrapping illudin S in liposome markedly enhanced life prolonging effect in ddN mice bearing Ehrlich ascites tumors, presumably by decreasing the side effects.We thank Mr M. Yabe for various technical assistance.     

Reevaluation of hydropathy profiles of voltage-gated ionic channels

A reevaluation of the secondary structure of Na, Ca and K channel proteins led to the following results. Only three segments (S1, S5 and S6) of each repeat are sufficiently hydrophobic to be predicted as transmembrane helices, if a window of 19 amino acids is used. Some of the S2 and S3 segments show higher hydrophobic values when calculated with the window of 9 amino acids and can be predicted as short helices. S4 segments are strongly hydrophilic and cannot be predicted as transmembrane helices. Some of the S2, S3 and S4 segments have an amphipathic character; however, these helices do not span a membrane. A model is proposed where 12 hydrophobic transmembrane helices surround 12 shorter helices, forming a hydrophilic pore. In addition, a unique pattern for S4 segments of voltage-gated channel proteins is defined.     

Reevaluation of hydropathy profiles of voltage-gated ionic channels

A reevaluation of the secondary structure of Na, Ca and K channel proteins led to the following results. Only three segments (S1, S5 and S6) of each repeat are sufficiently hydrophobic to be predicted as transmembrane helices, if a window of 19 amino acids is used. Some of the S2 and S3 segments show higher hydrophobic values when calculated with the window of 9 amino acids and can be predicted as short helices. S4 segments are strongly hydrophilic and cannot be predicted as transmembrane helices. Some of the S2, S3 and S4 segments have an amphipathic character; however, these helices do not span a membrane. A model is proposed where 12 hydrophobic transmembrane helices surround 12 shorter helices, forming a hydrophilic pore. In addition, a unique pattern for S4 segments of voltage-gated channel proteins is defined.     

从近年科技投入变化看美国科技政策的变化

美国能够成为世界头号科技大国，其科技政策功不可没。近年来，美国不断调整其科技政策以保证站在世界的最前列，这可以从美国在科技中投入的不断变化看出来。本文基于冷战结束至今美国在科技中投入的变化，分析了美国科技政策十几年来的变化特点。     

区域建筑业科技竞争力综合评价与分析———基于中国各省市面板数据的实证研究

依据相关模型,提出了区域建筑业科技竞争力的评价指标体系,利用因子分析法对2010年全国30个省市的建筑业科技竞争力进行了测度和分析.实证结果显示,建筑业科技竞争力主要受到科技投入、技术基础、科技产出和科技保障四个方面要素的影响     

Movements of supernumerary hindlimbs after innervation by single lumbar spinal nerves of Xenopus laevis.

Lumbar spinal nerves S8, S9, and S10, together innervating normal hindlimbs in Xenopus laevis, were tested to cause coordinated movements in grafted hindlimbs. It could be shown that this ability is mainly restricted to lumbar nerve S9.     

Sphingosine 1-phosphate increases glucose uptake through trans-activation of insulin receptor

Sphingosine 1-phosphate (S1P) is a bioactive lipid that acts through a family of G-protein-coupled receptors. Herein, we report evidence of a novel redox-based cross-talk between S1P and insulin signaling pathways. In skeletal muscle cells S1P, through engagement of its S1P₂ receptor, is found to produce a transient burst of reactive oxygen species through a calcium-dependent activation of the small GTPase Rac1. S1P-induced redox-signaling is sensed by protein tyrosine phosphatase-1B, the main negative regulator of insulin receptor phosphorylation, which undergoes oxidation and enzymatic inhibition. This redox-based inhibition of the phosphatase provokes a ligand-independent trans-phosphorylation of insulin receptor and a strong increase in glucose uptake. Our results propose a new role of S1P, recognizing the lipid as an insulin-mimetic cue and pointing at reactive oxygen species as critical regulators of the cross-talk between S1P and insulin pathways. Any possible implication of S1P-directed insulin signaling in diabetes and insulin resistance remains to be established.     

Die Isolierung von Ribonukleinsäuren aus menschlichen Knochenmarkzellen

Summary By use of bentonite and sodium dodecylsulfate, which bind or inhibit ribonucleases, pure RNA preparations were obtained from human bone marrow. Phenol extraction at 4 °C yielded cytoplasmic RNA, which could be separated into 3 main peaks by sucrose density gradient centrifugation. Sedimentation coefficients of these peaks were about 30S, 19S, and 5S, respectively. Re-extraction of the phenolic interphase at 65° gave a polydisperse ribonucleic acid, sedimenting between 2S and 19S. This RNA is characterized by template activity and is supposed to be biologically active m-RNA.     

Ubiquitin-proteasome system

The 26S proteasome is the multi-protein protease that recognizes and degrades ubiquitinylated substrates targeted for destruction by the ubiquitin pathway. In addition to the well-documented subunit organization of the 26S holoenzyme, it is clear that a number of other proteins transiently associate with the 26S complex. These transiently associated proteins confer a number of different roles such as substrate presentation, cleavage of the multi-ubiquitin chain from the protein substrate and turnover of misfolded proteins. Such activities are essential for the 26S proteasome to efficiently fulfill its intracellular function in protein degradation.     

The influence of sodium-8-chlorotheophyllinate (S8CT) on immune processes

Summary S8CT injected at the time of immunization significantly enhances specific IgM-production but has no effect on IgG-formation. Mitogen (PHA-P) induced macrophage migration inhibition of cells of S8CT pretreated animals is reduced. The same effect is observed, when normal cells are tested in the presence of S8CT in vitro. Blast transformation of B-lymphocytes but not of thymocytes is significantly stimulated by S8CT. Acid phosphatase activity is also stimulated in B-cells and- to a lesser degree-in cortisone-resistant T-lymphocytes whereas the activity of the total thymocyte population is reduced. No effect was seen on phagocytosis and intracellular bactericidal activity. A stimulatory effect of S8CT for B-cells is postulated.Presented in part at the Xth International Congress of Allergology and Clinical Immunology, Jerusalem/Israel 1979, Nov. 4–11.     

国际科技合作中知识转移风险的研究

随着科技全球化的发展和深入,国际科技合作成为各国政府和科研机构提升自身科研水平和核心竞争力的有力途径。然而,在国际科技合作中进行知识的转移与交流时,不可避免的面临着各种各样的风险,如何识别扣防范这些风险成为目前亟待解决的议题。有鉴于此,本文从知识、合作成员和环境三个维度,系统的对国际科技合作中的知识转移风险因素进行了分析,并据此进一步构建出相应的风险防范机制模型,力图为降低国际科技中的知识转移风险提供科学的理论依据。     

S100A6 protein: functional roles

S100A6 protein belongs to the A group of the S100 protein family of Ca²⁺-binding proteins. It is expressed in a limited number of cell types in adult normal tissues and in several tumor cell types. As an intracellular protein, S100A6 has been implicated in the regulation of several cellular functions, such as proliferation, apoptosis, the cytoskeleton dynamics, and the cellular response to different stress factors. S100A6 can be secreted/released by certain cell types which points to extracellular effects of the protein. RAGE (receptor for advanced glycation endproducts) and integrin β1 transduce some extracellular S100A6’s effects. Dosage of serum S100A6 might aid in diagnosis in oncology.     

Sphingosine 1-phosphate induces differentiation of adipose tissue-derived mesenchymal stem cells towards smooth muscle cells

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid which regulates multiple biological parameters in a number of cell types, including stem cells. Here we report, for the first time, that S1P dose-dependently stimulates differentiation of adipose tissue-derived mesenchymal stem cells (ASMC) towards smooth muscle cells. Indeed, S1P not only induced the expression of smooth muscle cell-specific proteins such as α-smooth muscle actin (αSMA) and transgelin, but also profoundly affected ASMC morphology by enhancing cytoskeletal F-actin assembly, which incorporated αSMA. More importantly, S1P challenge was responsible for the functional appearance of Ca²⁺ currents, characteristic of differentiated excitable cells such as smooth muscle cells. By employing various agonists and antagonists to inhibit S1P receptor subtypes, S1P₂ turned out to be critical for the pro-differentiating effect of S1P, while S1P₃ appeared to play a secondary role. This study individuates an important role of S1P in AMSC which can be exploited to favour vascular regeneration. Received 06 March 2009; accepted 17 March 2009     

Molecular forms of acetylcholinesterase in the chicken ciliary ganglion; changes after denervation, axotomy and double section]

Four main molecular forms of acetylcholinesterase (AChE), with sedimentation coefficients of 5, 7.5, 11.5 and 20 S, are found in Chicken ciliary ganglion. After denervation, the loss in 11.5 and 20 S forms occuring in 48 hrs coincides with the disappearance of presynaptic structures. In contrast, axotomy induces an early and durable increase in 7.5 S form. From these results, it is inferred that 11.5 and 20 S forms are predominant in presynaptic structures and 7.5 S form is mainly postsynaptic. In addition, the effects observed after simultaneous denervation and axotomy show a reciprocal control between pre- and postsynaptic elements. Finally, a trans-synaptic effect is exerted on 20 S AChE in controlateral ganglion after preganglionic sections.     

国外政府科技评估的新趋势及与我国的对比分析

首先对目前国外政府在组织实施科技评估的过程中呈现出的一些新特点和趋势进行了分析与总结。在此基础上，对国内外政府在组织实施科技评估过程中存在的一些不同之外进行了对比分析。最后就如何借鉴国外经验更好地组织开展我国政府科技评估工作进行了的讨论。     

Joining S100 proteins and migration: for better or for worse,in sickness and in health

The vast diversity of S100 proteins has demonstrated a multitude of biological correlations with cell growth, cell differentiation and cell survival in numerous physiological and pathological conditions in all cells of the body. This review summarises some of the reported regulatory functions of S100 proteins (namely S100A1, S100A2, S100A4, S100A6, S100A7, S100A8/S100A9, S100A10, S100A11, S100A12, S100B and S100P) on cellular migration and invasion, established in both culture and animal model systems and the possible mechanisms that have been proposed to be responsible. These mechanisms involve intracellular events and components of the cytoskeletal organisation (actin/myosin filaments, intermediate filaments and microtubules) as well as extracellular signalling at different cell surface receptors (RAGE and integrins). Finally, we shall attempt to demonstrate how aberrant expression of the S100 proteins may lead to pathological events and human disorders and furthermore provide a rationale to possibly explain why the expression of some of the S100 proteins (mainly S100A4 and S100P) has led to conflicting results on motility, depending on the cells used.     

Cdk5 targets active Src for ubiquitin-dependent degradation by phosphorylating Src(S75)

The non-receptor tyrosine kinase Src is a critical regulator of cytoskeletal contraction, cell adhesion, and migration. In normal cells, Src activity is stringently controlled by Csk-dependent phosphorylation of Src(Y530), and by Cullin-5-dependent ubiquitinylation, which affects active Src(pY419) exclusively, leading to its degradation by the proteosome. Previous work has shown that Src activity is also limited by Cdk5, a proline-directed kinase, which has been shown to phosphorylate Src(S75). Here we show that this phosphorylation promotes the ubiquitin-dependent degradation of Src, thus restricting the availability of active Src. We demonstrate that Src(S75) phosphorylation occurs in vivo in epithelial cells, and like ubiquitinylation, is associated only with active Src. Preventing Cdk5-dependent phosphorylation of Src(S75), by site-specific mutation of S75 or by Cdk5 inhibition or suppression, increases Src(Y419) phosphorylation and kinase activity, resulting in Src-dependent cytoskeletal changes. In transfected cells, ubiquitinylation of Src(S75A) is about 35% that of wild-type Src-V5, and its half-life is approximately 2.5-fold greater. Cdk5 suppression leads to a comparable decrease in the ubiquitinylation of endogenous Src and a similar increase in Src stability. Together, these findings demonstrate that Cdk5-dependent phosphorylation of Src(S75) is a physiologically significant mechanism of regulating intracellular Src activity.     

The Sushi peptides: structural characterization and mode of action against Gram-negative bacteria

The compositional difference in microbial and human cell membranes allows antimicrobial peptides to preferentially bind microbes. Peptides which specifically target lipopolysaccharide (LPS) and palmitoyl-oleoyl-phosphatidylglycerol (POPG) are efficient antibiotics. From the core LPS-binding region of Factor C, two 34-mer Sushi peptides, S1 and S3, were derived. S1 functions as a monomer, while S3 is active as a dimer. Both S1 and S3 display detergent-like properties in disrupting LPS aggregates, with specificity for POPG resulting from electrostatic and hydrophobic forces between the peptides and the bacterial lipids. During interaction with POPG, the S1 transitioned from a random coil to an α-helix, while S3 resumed a mixture of α-helix and β-sheet structures. The unsaturated nature of POPG confers fluidity and enhances insertion of the peptides into the lipid bilayer, causing maximal disruption of the bacterial membrane. These parameters should be considered in designing and developing new generations of peptide antibiotics with LPS-neutralizing capability. Received 2 October 2007; received after revision 2 November 2007; accepted 4 December 2007 J. L. Ding, B. Ho: Co-senior authors.