Glycolytic oligodendrocytes maintain myelin and long-term axonal integrity

Oligodendrocytes, the myelin-forming glial cells of the central nervous system, maintain long-term axonal integrity. However, the underlying support mechanisms are not understood. Here we identify a metabolic component of axon-glia interactions by generating conditional Cox10 (protoheme IX farnesyltransferase) mutant mice, in which oligodendrocytes and Schwann cells fail to assemble stable mitochondrial cytochrome c oxidase (COX, also known as mitochondrial complex IV). In the peripheral nervous system, Cox10 conditional mutants exhibit severe neuropathy with dysmyelination, abnormal Remak bundles, muscle atrophy and paralysis. Notably, perturbing mitochondrial respiration did not cause glial cell death. In the adult central nervous system, we found no signs of demyelination, axonal degeneration or secondary inflammation. Unlike cultured oligodendrocytes, which are sensitive to COX inhibitors, post-myelination oligodendrocytes survive well in the absence of COX activity. More importantly, by in vivo magnetic resonance spectroscopy, brain lactate concentrations in mutants were increased compared with controls, but were detectable only in mice exposed to volatile anaesthetics. This indicates that aerobic glycolysis products derived from oligodendrocytes are rapidly metabolized within white matter tracts. Because myelinated axons can use lactate when energy-deprived, our findings suggest a model in which axon-glia metabolic coupling serves a physiological function.     

Regulation of synaptic connectivity by glia

The human brain contains more than 100 trillion (10(14)) synaptic connections, which form all of its neural circuits. Neuroscientists have long been interested in how this complex synaptic web is weaved during development and remodelled during learning and disease. Recent studies have uncovered that glial cells are important regulators of synaptic connectivity. These cells are far more active than was previously thought and are powerful controllers of synapse formation, function, plasticity and elimination, both in health and disease. Understanding how signalling between glia and neurons regulates synaptic development will offer new insight into how the nervous system works and provide new targets for the treatment of neurological diseases.     

异构系统信息集成的数据仓库方法

从某制造型企业信息系统现状出发,说明企业信息集成的重要性,提出了采用数据仓库的方法,在企业原有异构信息系统的基础上进行信息集成,并结合该企业实际情况,说明了这个方法的实现过程。     

数据完整性机制的研究与实现

为了保证数据库中数据的准确性、一致性,数据库设计者应合理设计数据表的数据完整性。SQL Server数据库管理系统作为微软的核心产品,可以通过主键、标识列、惟一键、检查约束、外键约束等手段实现实体完整性、域完整性和参照完整性,参照完整性是保证数据一致性的重要机制,SQL Server中的触发器也可以实现参照完整性,以保证数据表间的插入规则、更新规则和删除规则的约定。     

传统诚信思想在大学生诚信教育中的价值

中华传统文化中的诚信资源极其丰富,在大学生诚信教育过程中极具借鉴和继承作用.通过对传统诚信思想的解读和阐释发现,先秦诸子的诚信思想虽各有侧重,但儒家的诚信思想则更为丰富和系统,而且其影响也最为深远.     

基于不变矩和支持向量机理论的船舰目标识别

基于支持向量机(Support Vector Machine,SVM)理论和不变矩(Invariant Moments)理论,提出一种船舰目标识别方法。首先,对图像进行预处理,将彩色图像转化为灰度图像;然后利用Hu不变矩来提取图像的七个不变矩特征;最后,选用支持向量机作为分类器,并将计算出的图像的七个矩特征作为支持向量机的输入对支持向量机进行训练和测试。实验证明,将不变矩特征提取方法与SVM相结合用于模式识别,可以得到很高的分类效率和准确率。     

CENP-B preserves genome integrity at replication forks paused by retrotransposon LTR

Centromere-binding protein B (CENP-B) is a widely conserved DNA binding factor associated with heterochromatin and centromeric satellite repeats. In fission yeast, CENP-B homologues have been shown to silence long terminal repeat (LTR) retrotransposons by recruiting histone deacetylases. However, CENP-B factors also have unexplained roles in DNA replication. Here we show that a molecular function of CENP-B is to promote replication-fork progression through the LTR. Mutants have increased genomic instability caused by replication-fork blockage that depends on the DNA binding factor switch-activating protein 1 (Sap1), which is directly recruited by the LTR. The loss of Sap1-dependent barrier activity allows the unhindered progression of the replication fork, but results in rearrangements deleterious to the retrotransposon. We conclude that retrotransposons influence replication polarity through recruitment of Sap1 and transposition near replication-fork blocks, whereas CENP-B counteracts this activity and promotes fork stability. Our results may account for the role of LTR in fragile sites, and for the association of CENP-B with pericentromeric heterochromatin and tandem satellite repeats.     

Retrograde axonal transport of target tissue-derived macromolecules

Neurones depend on contact with their target tissues for survival and subsequent development. The protein, nerve growth factor (NGF), can be selectively taken up by sympathetic nerve terminals and reaches the neuronal perikaryon by a process of retrograde intra-axonal transport, suggesting that its role in vivo is to act as a target tissue-derived trophic factor. The development of the neurones of the chick ciliary ganglion requires the presence of structures derived from the optic cup. Several studies in vitro have shown that media conditioned by non-neuronal cells contain factors that result in the survival of neurones from ciliary ganglia. In particular, chick embryo iris, ciliary body and choroid contained large amounts of these factors indicating the presence of a target tissue-derived trophic factor for the cholinergic ciliary ganglion. This study demonstrates that neurones of the ciliary ganglion accumulate, by retrograde intra-axonal transport, proteins synthesized and released by optic tissues in culture.     

The integrity of the scientific literature

A case of admitted scientific fraud has shed new light on the system that ensures the integrity of the scientific literature. Certain lapses from generally accepted standards of research may be more frequent than is commonly believed.     

浅析VFP的数据完整性

数据完整性是数据库的基本要求。对Visual FoxPro的数据完整性的约束机制进行了概括和分析。     

简评战后日本对中国的赔偿与援助问题

二战后中国政府放弃对日本的赔偿要求，日本政府对华援助是中日两国关系中的重大事件，这两个事件对日本和中国的现代化建设、对中日两国友好关系的发展，都起到了重要的促进作用。但是，日本政府对华援助则有许多自身考虑的因素。     

微弧氧化法制备负载型催化剂载体的研究

以TA1钛丝网为基体,用微弧氧化法在其表面制得TiO2薄膜作为催化氧化催化剂的载体.采用XRD、SEM、BET等分析方法,对所制备的载体进行了表征.对TiO2薄膜的晶体结构、表面形貌和比表面积进行了载体性能的研究.结果表明,H2SO4浓度为0.6 mol/L,电流密度为14 A/dm2,反应时间为5 min时,TiO2薄膜表面的微孔较多并且分布均匀,比表面积最大,满足负载活性组分要求.     

用信息技术支撑企业生产发展

根据云铜生产管理模式,综合应用计算机技术、实时数据采集技术、网络通信技术和管控一体化技术,建立生产管理信息系统,实现生产管理信息化．     

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。     

基于加权近似支持向量机的文本分类

随着因特网的迅速增长,能够分类大规模文档的高效文本分类算法变得非常重要.该文提出一种基于加权近似支持向量机模型的文本分类算法,加权近似支持向量机对近似支持向量机作了改进,通过为每个训练误差增加一个权值和使用在原空间直接求解的算法,克服了近似支持向量机模型不适合不平衡数据分类和高维数据分类的缺点.试验结果表明,与标准支持向量机算法相比,该算法的分类质量与训练速度都有提高,是一种适合文本分类的高效算法.     

论“三个代表”与“五种精神”的统一性

“三个代表”的重要思想,是党的宗旨、根本性质和历史任务的新的、全面完整的概括;它具有创新性、实践性和统一性;“五种精神”是“三个代表”重要思想的进一步延伸,是对全党全社会应确立的思想境界和世界观、人生观、价值观的要求,它具有时代特征和统一性;二者是指导各项工作的指导思想和行动纲领。