The <Emphasis Type="Italic">Adhesion</Emphasis> GPCRs: A unique family of G protein-coupled receptors with important roles in both central and peripheral tissues

G protein-coupled receptors (GPCRs) are a diverse superfamily of membrane-bound receptors. The second largest subgroup of GPCRs, the Adhesion GPCRs, has 33 members in humans. Phylogenetic analysis of the entire repertoire of the seven transmembrane- domain (7TM) regions of GPCRs shows that the Adhesion GPCRs form a distinct family. Adhesion GPCRs are characterised by (1) long N termini with multiple functional domains often found in other proteins such as tyrosine kinases, integrins and cadherins, (2) highly complex genomic structure with multiple introns and splice variants and (3) a 7TM region that has no clear similarities with 7TM from other GPCRs. Several Adhesion GPCRs are known to have a role in the immune system but it is becoming more evident that many have important roles in the CNS. We speculate that the overall structural construction of the Adhesion GPCRs allows them to participate in different types of cell guidance. Received 8 February 2007; received after revision 21 March 2007; accepted 25 April 2007     

七元瓜环对小鼠的急性毒性实验研究

研究七元瓜环以合理的给药浓度和最大给药容积给KM小鼠灌胃给药后动物产生的急性毒性反应,为该大环化合物能否作为安全的药物载体提供毒理学依据。实验中小鼠未出现死亡,未测出瓜环的LD50,因此测定其最大给药量。结果表明动物在最大给药剂量为15g/kg时未出现毒性反应,无一动物死亡,提示七元瓜环毒性很低,能作为一种安全、低毒的药物载体。     

Disordered RNA chaperone proteins: from functions to disease

RNA chaperones are ubiquitous proteins that play pivotal roles in cellular RNA metabolism and RNA virus replication. Here we propose that they act by organizing complex and highly dynamic networks of RNA-RNA, RNA-protein and protein-protein interactions. How this is achieved and how their malfunction may lead to disease will be discussed through the examples of human immunodeficiency virus type 1 nucleocapsid protein (NCp7), the fragile X mental retardation protein and the prion protein.Received 9 March 2005; received after revision 6 April 2005; accepted 6 April 2005Dedicated to the memory of Dominique Dormont     

APC/C regulation of axonal growth and synaptic functions in postmitotic neurons: the Liprin-{\varvec \alpha} connection

Protein ubiquitination has critical roles in neuronal physiology and defects in protein ubiquitination have been implicated in neurodegenerative pathology. The anaphase-promoting complex/cyclosome (APC/C) is one of two key E3 ubiquitin ligase complexes that functions in regulating cell cycle transitions in proliferating cells by acting on cyclins and components of the mitotic/meiotic apparatus. Documentation of APC/C's action beyond cell division is sparse. In the past year, however, novel and surprising roles for APC/C in postmitotic neurons, particularly in the modulation of axonal growth and synaptic functions, have been revealed. APC/C and its activator Cdh-1 are found in good abundance in neurons, and these seem to function at different cellular locations, modulating apparently diverse processes such as axonal growth and synaptic function. Interestingly, there also appears to be a single link to these apparently divergent actions of APC/C in neurons--the multi-domain, multi-functional scaffolding protein Liprin-alpha which is an APC/C substrate.     

Kinetics of BRCA1 regulation in response to UVC radiation

To investigate changes in BRCA1 following DNA damage, we exposed MCF-7 cells to increasing doses of ultraviolet C. We observed an increase in BRCA1 protein levels above 78 J/m². This increase was observed as early as 5 min after irradiation. BRCA1 levels were then observed to decrease after 2 h, consistent with the previously published data. By pretreating with cycloheximide prior to irradiation, we observed a decrease in the protein half-life, from 3.5 h to 53 min, suggesting that a decrease in protein half-life may cause the lower levels of BRCA1 after irradiation. We also observed an increase in BRCA1 mRNA within 15 min of irradiation, followed by a decrease after 4 h. These data suggest that newly translated protein may contribute to increases in BRCA1 protein levels. The very rapid changes in BRCA1 support its role as a sensor of DNA damage, as opposed to being a repair gene. Received 6 April 2000; received after revision 23 May 2000; accepted 23 May 2000     

基于SVM的图像分类系统设计

为实现基于语义的图像分类,其本质还是从底层特征出发,因此,高层信息的学习和建模也就必须来源于底层特征了。在底层特征提取的基础上提出了一个基于SVM的图像分类系统的设计,重点介绍了图像数据库的设计和分类引擎的设计,说明了其可行性和方便易用性。最后展望了基于SVM的图像分类引擎技术的发展方向和应用前景。     

分光光度法测定微量钛的研究

研究了新显色剂2,6-二碘-4-硝基偶氮胂[化学名称为2-(2-胂酸基苯偶氮)-7-(2,6-二碘-4-硝基苯偶氮)-1,8-二羟基-3,6-萘二磺酸]与钛的显色反应.在1.50 mol/L HC l介质中,试剂与钛生成深色配合物,最大吸收波长611 nm,摩尔吸光系数为3.89×104L.mol-1.cm-1,显色酸度较高,常见共存离子允许量大,选择性较好.0~18μg/25mLTi(IV)符合比耳定律,直接吸光光度法测定合金钢中的微量钛.     

呼叫中心7号信令网关的设计

呼叫中心中将1号信令改为7号信令可以降低中继成本,提高客户满意度.系统设计采用Client/Server结构及基于Socket事件的激发机制,可以将7号信令的底层细节加以屏蔽,以高层的接口协议方式通信,以实现计算机局域网协议与7号信令协议的转换,且系统运行稳定.     

7号信令监测系统在互联互通业务中的研究与实现

在互联互通业务中应用7号信令集中监测系统，可以为电信运营商进行市场分析和制定经营策略提供重要的帮助。在深入研究7号信令网和7号信令监测系统基本原理的基础上，提出了一种新的信令事件合成方法，并详述了这种方法的基本思路和具体的实施方式，最后给出了采用该方法的监测系统在互联互通业务中的具体实现方案。     

4(5),4′(5′)-二烷基二苯并-21-冠-7的合成

在PPA存在下，长链羧酸与二苯并-21-冠-7进行烷酰化反应，制得了4(5)，4′(5′)-二烷基二苯并-21-冠-7(1a～c)，随后用黄鸣龙法还原成标题化合物2a～c．它们均经元素分析，红外光谱，核磁共振氢谱和质谱进行了表征。